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INDESTRUCTIBLE SPACES WITH STRONG
CCC
              SEPARABILITY
                 AND SEPARABILITY IN 2ω1
          MAℵ1


                   Erik A. Andrejko

             University of Wisconsin - Madison


                      Feb 27 2007




            ERIK A. ANDREJKO          INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                CCC
CH TO MAℵ1 TO PFA




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
CH TO MAℵ1 TO PFA




      THFD
        HFD HFDwω

       HFDw
                   ω
    O-space S-space
    S-space




                   ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                      CCC
CH TO MAℵ1 TO PFA




                                                               THFD
      THFD
                                                               HFD HFDwω
        HFD     ω
             HFDw
                                                              HFDw
       HFDw
                                                                          ω
                                                           O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
CH TO MAℵ1 TO PFA




                                ?
                                                               THFD
      THFD
                                                               HFD HFDwω
        HFD     ω
             HFDw
                                                              HFDw
       HFDw
                                                                          ω
                                                           O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
SEPARABILITY




               ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                  CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).

  DEFINITION
  X is separable if X has a countable dense subset.




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).

  DEFINITION
  X is separable if X has a countable dense subset.
  X is hereditarily separable if every subspace has a countable dense
  subset.




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).

  DEFINITION
  X is separable if X has a countable dense subset.
  X is hereditarily separable if every subspace has a countable dense
  subset.
  If X is hereditarily separable and not Lindelöf then X is called an
  S-space.




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).

  DEFINITION
  X is separable if X has a countable dense subset.
  X is hereditarily separable if every subspace has a countable dense
  subset.
  If X is hereditarily separable and not Lindelöf then X is called an
  S-space.

  DEFINITION
  A is finally dense if for some γ < ω1 A is dense in 2ω1 γ .




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
SEPARABILITY


  Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular).

  DEFINITION
  X is separable if X has a countable dense subset.
  X is hereditarily separable if every subspace has a countable dense
  subset.
  If X is hereditarily separable and not Lindelöf then X is called an
  S-space.

  DEFINITION
  A is finally dense if for some γ < ω1 A is dense in 2ω1 γ .
  X is a weak HFD iff for all Y ∈ [X ]ω1 there is some A ∈ [Y ]ω such that
  A is finally dense.



                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
SEPARABILITY


  DEFINITION
  X is a HFD iff for all A ∈ [X ]ω , A is finally dense.




                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
SEPARABILITY


  DEFINITION
  X is a HFD iff for all A ∈ [X ]ω , A is finally dense.

  LEMMA
  If there is an HFD, there is a weak HFD. If there is a weak HFD, there
  is an S-space.




                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
SEPARABILITY


  DEFINITION
  X is a HFD iff for all A ∈ [X ]ω , A is finally dense.

  LEMMA
  If there is an HFD, there is a weak HFD. If there is a weak HFD, there
  is an S-space.



                                    HFD
                                    HFDw

                               S-space



                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
O-SPACES




           ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                              CCC
O-SPACES

  DEFINITION
  X is an O-space iff every open set is countable or co-countable.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
O-SPACES

  DEFINITION
  X is an O-space iff every open set is countable or co-countable.

  LEMMA
  If there is a weak HFD there is an O-space. If there is an O-space,
  there is S-space.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
O-SPACES

  DEFINITION
  X is an O-space iff every open set is countable or co-countable.

  LEMMA
  If there is a weak HFD there is an O-space. If there is an O-space,
  there is S-space.



                                  HFD
                                  HFDw

                             S-space




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
O-SPACES

  DEFINITION
  X is an O-space iff every open set is countable or co-countable.

  LEMMA
  If there is a weak HFD there is an O-space. If there is an O-space,
  there is S-space.



                                HFD
                               HFDw
                            O-space
                            S-space




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONG SPACES




                ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                   CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space




                     ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                        CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space if every finite power X n is a
  Φ space. e.g. HFDw , S-space.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space if every finite power X n is a
  Φ space. e.g. HFDw , S-space.

  THEOREM
  (CH) There exists a strong HFDw ,




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space if every finite power X n is a
  Φ space. e.g. HFDw , S-space.

  THEOREM
  (CH) There exists a strong HFDw , and hence a strong S-space.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space if every finite power X n is a
  Φ space. e.g. HFDw , S-space.

  THEOREM
  (CH) There exists a strong HFDw , and hence a strong S-space.

  COROLLARY
  (CH) There exists a HFDn space and S-spacen for all n < ω.
                         w




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONG SPACES

  DEFINITION
  A Φ space X is called a strong Φ space if every finite power X n is a
  Φ space. e.g. HFDw , S-space.

  THEOREM
  (CH) There exists a strong HFDw , and hence a strong S-space.

  COROLLARY
  (CH) There exists a HFDn space and S-spacen for all n < ω.
                         w


  THEOREM
  (CH) There exists an HFD.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
SPACES UNDER CH




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
SPACES UNDER CH



                      HFD
                     HFDw
                  O-space
                  S-space




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
SPACES UNDER CH



                      HFD HFDwω

                     HFDw
                                 ω
                  O-space S-space
                  S-space




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
EXISTENCE AND NONEXISTENCE




  THEOREM (ROITMAN)
  Let r be a Cohen real.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
EXISTENCE AND NONEXISTENCE




  THEOREM (ROITMAN)
  Let r be a Cohen real.

                           V [r ] |= ∃a strong HFD




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
EXISTENCE AND NONEXISTENCE




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
EXISTENCE AND NONEXISTENCE



  THEOREM
  (MAℵ1 ) There are no HFDs.




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
EXISTENCE AND NONEXISTENCE



  THEOREM
  (MAℵ1 ) There are no HFDs.

  LEMMA (SILVER’S LEMMA)
  Assume MAℵ1 (or p > ω1 ).




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
EXISTENCE AND NONEXISTENCE



  THEOREM
  (MAℵ1 ) There are no HFDs.

  LEMMA (SILVER’S LEMMA)
  Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of
  ω1 .




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
EXISTENCE AND NONEXISTENCE



  THEOREM
  (MAℵ1 ) There are no HFDs.

  LEMMA (SILVER’S LEMMA)
  Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of
  ω1 . Then there is an infinite E ⊆ ω such that either

                               An
                         n∈E




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
EXISTENCE AND NONEXISTENCE



  THEOREM
  (MAℵ1 ) There are no HFDs.

  LEMMA (SILVER’S LEMMA)
  Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of
  ω1 . Then there is an infinite E ⊆ ω such that either

                                               (ω1  An )
                               An or
                         n∈E             n∈E

  is uncountable.




                      ERIK A. ANDREJKO               INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                               CCC
EXISTENCE AND NONEXISTENCE




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
EXISTENCE AND NONEXISTENCE

  COROLLARY
  If V |= MAℵ1 , and r is a Cohen real, then V [r ] |= MAℵ1 .




                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
EXISTENCE AND NONEXISTENCE

  COROLLARY
  If V |= MAℵ1 , and r is a Cohen real, then V [r ] |= MAℵ1 .

  THEOREM (KUNEN)
  (MAℵ1 ) There are no strong S-spaces.




                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
UNDER MAℵ1




             ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                CCC
UNDER MAℵ1


                                                               THFD
      THFD
                                                               HFD HFDwω
        HFD     ω
             HFDw
                                                              HFDw
       HFDw
                                                                          ω
                                                           O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
UNDER MAℵ1




                                ?
                                                               THFD
      THFD
                                                               HFD HFDwω
        HFD     ω
             HFDw
                                                              HFDw
       HFDw
                                                                          ω
                                                           O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
UNDER MAℵ1


                                                               THFD
                               THFD
      THFD
                                                               HFD HFDw
                                HFD                                    ω
        HFD                               ω
                ω
                                       HFDw
             HFDw
                                                              HFDw
       HFDw
                                                                          ω
                                       S-spaceω            O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
UNDER MAℵ1


                                                               THFD
                               THFD
      THFD
                                                               HFD HFDw
                                HFD                                    ω
        HFD                               ω
                ω
                                       HFDw
             HFDw



                                ?
                                                              HFDw
       HFDw
                                                                          ω
                                       S-spaceω            O-space S-space
                   ω
    O-space S-space
                                                           S-space
    S-space




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
UNDER MAℵ1


                                                                 THFD
                                 THFD
       THFD
                                                                 HFD HFDw
                                  HFD                                    ω
         HFD                                ω
                 ω
                                         HFDw
              HFDw



                                  ?
                                                                HFDw
        HFDw
                                                                            ω
                                         S-spaceω            O-space S-space
                    ω
     O-space S-space
                                                             S-space
     S-space




  QUESTION
  Does there exist an S-space, O-space, or weak HFD under MAℵ1 ?
  Finite powers?




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
INDESTRUCTIBLE SPACES
CCC




                 ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                    CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,

                      V |= ϕ(X )




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,

                      V |= ϕ(X ) =⇒ V [G] |= ϕ(X )




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,

                      V |= ϕ(X ) =⇒ V [G] |= ϕ(X )



  e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space
  in any ccc extension.




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,

                      V |= ϕ(X ) =⇒ V [G] |= ϕ(X )



  e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space
  in any ccc extension.

  DEFINITION
  Let X be an S-space.




                         ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
INDESTRUCTIBLE SPACES
CCC



  DEFINITION
  A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and
  any P-generic filter G over V ,

                      V |= ϕ(X ) =⇒ V [G] |= ϕ(X )



  e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space
  in any ccc extension.

  DEFINITION
  Let X be an S-space. Then let PX be the natural order to add an
  uncountable discrete subspace with finite conditions.



                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC




                 ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                    CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type,




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω :




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω :

                              [ε] ∩ A is tight in A




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω :

                              [ε] ∩ A is tight in A

  Let A, B we well ordered of type α, β < ω1 limit ordinals.




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω :

                              [ε] ∩ A is tight in A

  Let A, B we well ordered of type α, β < ω1 limit ordinals. Then A is
  tight in B iff for some n,




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE SPACES
CCC



  THEOREM (SZENTMIKLÓSSY)
  If X is a ccc destructible S-space, then some uncountable A ⊆ PX has
  ccc.

  DEFINITION
  X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit
  type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω :

                              [ε] ∩ A is tight in A

  Let A, B we well ordered of type α, β < ω1 limit ordinals. Then A is
  tight in B iff for some n, every interval of B of length n meets A.




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE S-SPACE
CCC




                 ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                    CCC
INDESTRUCTIBLE S-SPACE
CCC


  THEOREM (SZENTMIKLÓSSY)
  (CH) There exists a tight HFD.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
INDESTRUCTIBLE S-SPACE
CCC


  THEOREM (SZENTMIKLÓSSY)
  (CH) There exists a tight HFD.

  THEOREM (SZENTMIKLÓSSY)
  If X is a tight HFD, then X is a ccc indestructible S-space.




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE S-SPACE
CCC


  THEOREM (SZENTMIKLÓSSY)
  (CH) There exists a tight HFD.

  THEOREM (SZENTMIKLÓSSY)
  If X is a tight HFD, then X is a ccc indestructible S-space.




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE S-SPACE
CCC


  THEOREM (SZENTMIKLÓSSY)
  (CH) There exists a tight HFD.

  THEOREM (SZENTMIKLÓSSY)
  If X is a tight HFD, then X is a ccc indestructible S-space.


                                                                  THFD
                                   THFD
          THFD
                                                                  HFD HFDw
                                     HFD HFDw                             ω
           HFD HFDw                         ω
                   ω




                                    ?
                                                                 HFDw
          HFDw
                                                                             ω
                                           S-spaceω           O-space S-space
                      ω
       O-space S-space
                                                              S-space
       S-space




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRUCTIBLE S-SPACE
CCC


  THEOREM (SZENTMIKLÓSSY)
  (CH) There exists a tight HFD.

  THEOREM (SZENTMIKLÓSSY)
  If X is a tight HFD, then X is a ccc indestructible S-space.


                                                                  THFD
                                   THFD
          THFD
                                                                  HFD HFDw
                                     HFD HFDw                             ω
           HFD HFDw                         ω
                   ω

                                                                 HFDw
          HFDw
                                                                             ω
                                           S-spaceω           O-space S-space
                      ω
       O-space S-space
                                                              S-space
                                S-space
       S-space




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
STRONGLY SOLID GRAPHS




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
STRONGLY SOLID GRAPHS

  DEFINITION
  A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any
  domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are
  α < β < ω1 such that
                             [sα , sβ ] ⊆ G




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
STRONGLY SOLID GRAPHS

  DEFINITION
  A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any
  domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are
  α < β < ω1 such that
                             [sα , sβ ] ⊆ G




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
STRONGLY SOLID GRAPHS

  DEFINITION
  A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any
  domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are
  α < β < ω1 such that
                             [sα , sβ ] ⊆ G




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
STRONGLY SOLID GRAPHS

  DEFINITION
  A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any
  domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are
  α < β < ω1 such that
                             [sα , sβ ] ⊆ G




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
STRONGLY SOLID GRAPHS

  DEFINITION
  A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any
  domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are
  α < β < ω1 such that
                             [sα , sβ ] ⊆ G




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
STRONGLY SOLID GRAPHS




              ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                 CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X ,




                    ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                       CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that

                     GX is m-solid




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that

                     GX is m-solid ⇐⇒ X is HFDm
                                              w




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that

                     GX is m-solid ⇐⇒ X is HFDm
                                              w




  DEFINITION
  A graph G is strongly solid iff G is m-solid for every m < ω.




                       ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                          CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that

                     GX is m-solid ⇐⇒ X is HFDm
                                              w




  DEFINITION
  A graph G is strongly solid iff G is m-solid for every m < ω.

  THEOREM (SOUKUP)
  Let V |= quot;G is strongly solidquot;. For any m there is a P such that




                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
STRONGLY SOLID GRAPHS

  THEOREM (SOUKUP)
  For a space X , there is a graph GX such that

                     GX is m-solid ⇐⇒ X is HFDm
                                              w




  DEFINITION
  A graph G is strongly solid iff G is m-solid for every m < ω.

  THEOREM (SOUKUP)
  Let V |= quot;G is strongly solidquot;. For any m there is a P such that

                  V P |= quot;G is ccc-indestructibly m-solidquot;.



                        ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC




                 ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                    CCC
INDESTRICTIBLE m-SOLID
CCC

  Assume 2ω1 = ω2 .




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
INDESTRICTIBLE m-SOLID
CCC
                                                         ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
INDESTRICTIBLE m-SOLID
CCC
                                                         ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
        |Qη | = ω1
  1Pη




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
INDESTRICTIBLE m-SOLID
CCC
                                                            ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
        |Qη | = ω1 and so (2ω1 )V
                                    Pω2
                                          = ω2 .
  1Pη




                       ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                            CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.




                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.




                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.
          {
                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.
          {
                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.
          {
                                            {
                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
INDESTRICTIBLE m-SOLID
CCC
                                                           ◦
  Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that
         ◦
  1Pη |Qη | = ω1 and so (2ω1 )V
                                   Pω2
                                         = ω2 . Furthermore P satisfies the
  previous theorem.
          {
                                            {
                      ERIK A. ANDREJKO           INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                           CCC
ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                   CCC
?
                                                          THFD
  THFD
                                                          HFD HFDwω
    HFD HFDwω

                                                         HFDw
   HFDw
                                                                     ω
                                                      O-space S-space
               ω
O-space S-space
                                                      S-space
S-space




               ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                  CCC
THFD
                          THFD
  THFD
                                                          HFD HFDw
                           HFD                                    ω
    HFD HFDw                         ω
            ω
                                  HFDw



                           ?
                                                         HFDw
   HFDw
                                                                     ω
                                  S-spaceω            O-space S-space
               ω
O-space S-space
                                                      S-space
S-space




               ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                  CCC
THFD
                          THFD
  THFD
                                                          HFD HFDw
                          HFD                                     ω
    HFD HFDw                         ω
            ω
                                  HFDw
                                                         HFDw
                         HFDw
   HFDw
                                                                     ω
                                     ω
                                                      O-space S-space
               ω
                      O-space S-space
O-space S-space
                                                      S-space
                      S-space
S-space




               ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                  CCC
OPEN QUESTIONS




                 ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                    CCC
OPEN QUESTIONS



  Consistency questions:




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
OPEN QUESTIONS



  Consistency questions:

                HFD HFDwω

               HFDw
                           ω
            O-space S-space
            S-space




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
OPEN QUESTIONS



  Consistency questions:

                HFD HFDw                               HFD HFDw
                        ω                                      ω

               HFDw                                   HFDw
                           ω                                      ω
            O-space S-space                        O-space S-space
            S-space                                S-space




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
OPEN QUESTIONS



  Consistency questions:

                HFD HFDw                               HFD HFDw
                        ω                                      ω

               HFDw                                   HFDw
                           ω                                      ω
            O-space S-space                        O-space S-space
            S-space                                S-space




  QUESTION (JUHASZ)
  Does there exists a (c, →)-HFD?




                      ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                         CCC
REFERENCES




             ERIK A. ANDREJKO         INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY
                                CCC

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Ccc Indestructible S Spaces

  • 1. INDESTRUCTIBLE SPACES WITH STRONG CCC SEPARABILITY AND SEPARABILITY IN 2ω1 MAℵ1 Erik A. Andrejko University of Wisconsin - Madison Feb 27 2007 ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 2. CH TO MAℵ1 TO PFA ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 3. CH TO MAℵ1 TO PFA THFD HFD HFDwω HFDw ω O-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 4. CH TO MAℵ1 TO PFA THFD THFD HFD HFDwω HFD ω HFDw HFDw HFDw ω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 5. CH TO MAℵ1 TO PFA ? THFD THFD HFD HFDwω HFD ω HFDw HFDw HFDw ω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 6. SEPARABILITY ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 7. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 8. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). DEFINITION X is separable if X has a countable dense subset. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 9. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). DEFINITION X is separable if X has a countable dense subset. X is hereditarily separable if every subspace has a countable dense subset. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 10. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). DEFINITION X is separable if X has a countable dense subset. X is hereditarily separable if every subspace has a countable dense subset. If X is hereditarily separable and not Lindelöf then X is called an S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 11. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). DEFINITION X is separable if X has a countable dense subset. X is hereditarily separable if every subspace has a countable dense subset. If X is hereditarily separable and not Lindelöf then X is called an S-space. DEFINITION A is finally dense if for some γ < ω1 A is dense in 2ω1 γ . ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 12. SEPARABILITY Let X ⊆ 2ω1 be uncountable, zero-dimensional (hence regular). DEFINITION X is separable if X has a countable dense subset. X is hereditarily separable if every subspace has a countable dense subset. If X is hereditarily separable and not Lindelöf then X is called an S-space. DEFINITION A is finally dense if for some γ < ω1 A is dense in 2ω1 γ . X is a weak HFD iff for all Y ∈ [X ]ω1 there is some A ∈ [Y ]ω such that A is finally dense. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 13. SEPARABILITY DEFINITION X is a HFD iff for all A ∈ [X ]ω , A is finally dense. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 14. SEPARABILITY DEFINITION X is a HFD iff for all A ∈ [X ]ω , A is finally dense. LEMMA If there is an HFD, there is a weak HFD. If there is a weak HFD, there is an S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 15. SEPARABILITY DEFINITION X is a HFD iff for all A ∈ [X ]ω , A is finally dense. LEMMA If there is an HFD, there is a weak HFD. If there is a weak HFD, there is an S-space. HFD HFDw S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 16. O-SPACES ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 17. O-SPACES DEFINITION X is an O-space iff every open set is countable or co-countable. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 18. O-SPACES DEFINITION X is an O-space iff every open set is countable or co-countable. LEMMA If there is a weak HFD there is an O-space. If there is an O-space, there is S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 19. O-SPACES DEFINITION X is an O-space iff every open set is countable or co-countable. LEMMA If there is a weak HFD there is an O-space. If there is an O-space, there is S-space. HFD HFDw S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 20. O-SPACES DEFINITION X is an O-space iff every open set is countable or co-countable. LEMMA If there is a weak HFD there is an O-space. If there is an O-space, there is S-space. HFD HFDw O-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 21. STRONG SPACES ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 22. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 23. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space if every finite power X n is a Φ space. e.g. HFDw , S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 24. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space if every finite power X n is a Φ space. e.g. HFDw , S-space. THEOREM (CH) There exists a strong HFDw , ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 25. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space if every finite power X n is a Φ space. e.g. HFDw , S-space. THEOREM (CH) There exists a strong HFDw , and hence a strong S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 26. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space if every finite power X n is a Φ space. e.g. HFDw , S-space. THEOREM (CH) There exists a strong HFDw , and hence a strong S-space. COROLLARY (CH) There exists a HFDn space and S-spacen for all n < ω. w ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 27. STRONG SPACES DEFINITION A Φ space X is called a strong Φ space if every finite power X n is a Φ space. e.g. HFDw , S-space. THEOREM (CH) There exists a strong HFDw , and hence a strong S-space. COROLLARY (CH) There exists a HFDn space and S-spacen for all n < ω. w THEOREM (CH) There exists an HFD. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 28. SPACES UNDER CH ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 29. SPACES UNDER CH HFD HFDw O-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 30. SPACES UNDER CH HFD HFDwω HFDw ω O-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 31. EXISTENCE AND NONEXISTENCE THEOREM (ROITMAN) Let r be a Cohen real. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 32. EXISTENCE AND NONEXISTENCE THEOREM (ROITMAN) Let r be a Cohen real. V [r ] |= ∃a strong HFD ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 33. EXISTENCE AND NONEXISTENCE ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 34. EXISTENCE AND NONEXISTENCE THEOREM (MAℵ1 ) There are no HFDs. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 35. EXISTENCE AND NONEXISTENCE THEOREM (MAℵ1 ) There are no HFDs. LEMMA (SILVER’S LEMMA) Assume MAℵ1 (or p > ω1 ). ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 36. EXISTENCE AND NONEXISTENCE THEOREM (MAℵ1 ) There are no HFDs. LEMMA (SILVER’S LEMMA) Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of ω1 . ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 37. EXISTENCE AND NONEXISTENCE THEOREM (MAℵ1 ) There are no HFDs. LEMMA (SILVER’S LEMMA) Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of ω1 . Then there is an infinite E ⊆ ω such that either An n∈E ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 38. EXISTENCE AND NONEXISTENCE THEOREM (MAℵ1 ) There are no HFDs. LEMMA (SILVER’S LEMMA) Assume MAℵ1 (or p > ω1 ). Assume that {An : n < ω} are subsets of ω1 . Then there is an infinite E ⊆ ω such that either (ω1 An ) An or n∈E n∈E is uncountable. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 39. EXISTENCE AND NONEXISTENCE ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 40. EXISTENCE AND NONEXISTENCE COROLLARY If V |= MAℵ1 , and r is a Cohen real, then V [r ] |= MAℵ1 . ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 41. EXISTENCE AND NONEXISTENCE COROLLARY If V |= MAℵ1 , and r is a Cohen real, then V [r ] |= MAℵ1 . THEOREM (KUNEN) (MAℵ1 ) There are no strong S-spaces. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 42. UNDER MAℵ1 ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 43. UNDER MAℵ1 THFD THFD HFD HFDwω HFD ω HFDw HFDw HFDw ω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 44. UNDER MAℵ1 ? THFD THFD HFD HFDwω HFD ω HFDw HFDw HFDw ω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 45. UNDER MAℵ1 THFD THFD THFD HFD HFDw HFD ω HFD ω ω HFDw HFDw HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 46. UNDER MAℵ1 THFD THFD THFD HFD HFDw HFD ω HFD ω ω HFDw HFDw ? HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 47. UNDER MAℵ1 THFD THFD THFD HFD HFDw HFD ω HFD ω ω HFDw HFDw ? HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space QUESTION Does there exist an S-space, O-space, or weak HFD under MAℵ1 ? Finite powers? ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 48. INDESTRUCTIBLE SPACES CCC ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 49. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 50. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 51. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , V |= ϕ(X ) ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 52. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , V |= ϕ(X ) =⇒ V [G] |= ϕ(X ) ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 53. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , V |= ϕ(X ) =⇒ V [G] |= ϕ(X ) e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space in any ccc extension. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 54. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , V |= ϕ(X ) =⇒ V [G] |= ϕ(X ) e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space in any ccc extension. DEFINITION Let X be an S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 55. INDESTRUCTIBLE SPACES CCC DEFINITION A set X is said to be ccc-indestructibly ϕ iff for any ccc poset P and any P-generic filter G over V , V |= ϕ(X ) =⇒ V [G] |= ϕ(X ) e.g. If X is an S-space, then X is ccc-indestructible iff X is an S-space in any ccc extension. DEFINITION Let X be an S-space. Then let PX be the natural order to add an uncountable discrete subspace with finite conditions. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 56. INDESTRUCTIBLE SPACES CCC ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 57. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 58. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 59. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 60. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 61. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω : ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 62. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω : [ε] ∩ A is tight in A ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 63. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω : [ε] ∩ A is tight in A Let A, B we well ordered of type α, β < ω1 limit ordinals. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 64. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω : [ε] ∩ A is tight in A Let A, B we well ordered of type α, β < ω1 limit ordinals. Then A is tight in B iff for some n, ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 65. INDESTRUCTIBLE SPACES CCC THEOREM (SZENTMIKLÓSSY) If X is a ccc destructible S-space, then some uncountable A ⊆ PX has ccc. DEFINITION X ⊆ 2ω1 is a tight HFD iff X is an HFD and for every A ∈ [X ]ω of limit type, and associated β for every neighborhood ε ∈ [2ω1 β ]<ω : [ε] ∩ A is tight in A Let A, B we well ordered of type α, β < ω1 limit ordinals. Then A is tight in B iff for some n, every interval of B of length n meets A. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 66. INDESTRUCTIBLE S-SPACE CCC ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 67. INDESTRUCTIBLE S-SPACE CCC THEOREM (SZENTMIKLÓSSY) (CH) There exists a tight HFD. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 68. INDESTRUCTIBLE S-SPACE CCC THEOREM (SZENTMIKLÓSSY) (CH) There exists a tight HFD. THEOREM (SZENTMIKLÓSSY) If X is a tight HFD, then X is a ccc indestructible S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 69. INDESTRUCTIBLE S-SPACE CCC THEOREM (SZENTMIKLÓSSY) (CH) There exists a tight HFD. THEOREM (SZENTMIKLÓSSY) If X is a tight HFD, then X is a ccc indestructible S-space. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 70. INDESTRUCTIBLE S-SPACE CCC THEOREM (SZENTMIKLÓSSY) (CH) There exists a tight HFD. THEOREM (SZENTMIKLÓSSY) If X is a tight HFD, then X is a ccc indestructible S-space. THFD THFD THFD HFD HFDw HFD HFDw ω HFD HFDw ω ω ? HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 71. INDESTRUCTIBLE S-SPACE CCC THEOREM (SZENTMIKLÓSSY) (CH) There exists a tight HFD. THEOREM (SZENTMIKLÓSSY) If X is a tight HFD, then X is a ccc indestructible S-space. THFD THFD THFD HFD HFDw HFD HFDw ω HFD HFDw ω ω HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 72. STRONGLY SOLID GRAPHS ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 73. STRONGLY SOLID GRAPHS DEFINITION A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are α < β < ω1 such that [sα , sβ ] ⊆ G ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 74. STRONGLY SOLID GRAPHS DEFINITION A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are α < β < ω1 such that [sα , sβ ] ⊆ G ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 75. STRONGLY SOLID GRAPHS DEFINITION A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are α < β < ω1 such that [sα , sβ ] ⊆ G ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 76. STRONGLY SOLID GRAPHS DEFINITION A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are α < β < ω1 such that [sα , sβ ] ⊆ G ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 77. STRONGLY SOLID GRAPHS DEFINITION A graph G on ω1 × K and m ∈ ω. Then G is m-solid if given any domain disjoint sequence sα : α < ω1 ⊆ Fnm (ω1 , K ) there are α < β < ω1 such that [sα , sβ ] ⊆ G ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 78. STRONGLY SOLID GRAPHS ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 79. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 80. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 81. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that GX is m-solid ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 82. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that GX is m-solid ⇐⇒ X is HFDm w ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 83. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that GX is m-solid ⇐⇒ X is HFDm w DEFINITION A graph G is strongly solid iff G is m-solid for every m < ω. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 84. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that GX is m-solid ⇐⇒ X is HFDm w DEFINITION A graph G is strongly solid iff G is m-solid for every m < ω. THEOREM (SOUKUP) Let V |= quot;G is strongly solidquot;. For any m there is a P such that ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 85. STRONGLY SOLID GRAPHS THEOREM (SOUKUP) For a space X , there is a graph GX such that GX is m-solid ⇐⇒ X is HFDm w DEFINITION A graph G is strongly solid iff G is m-solid for every m < ω. THEOREM (SOUKUP) Let V |= quot;G is strongly solidquot;. For any m there is a P such that V P |= quot;G is ccc-indestructibly m-solidquot;. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 86. INDESTRICTIBLE m-SOLID CCC ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 87. INDESTRICTIBLE m-SOLID CCC Assume 2ω1 = ω2 . ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 88. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 89. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ |Qη | = ω1 1Pη ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 90. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . 1Pη ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 91. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 92. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 93. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. { ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 94. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. { ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 95. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. { { ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 96. INDESTRICTIBLE m-SOLID CCC ◦ Assume 2ω1 = ω2 . There is a P = Pω2 = Pη , Qη : η < ω2 such that ◦ 1Pη |Qη | = ω1 and so (2ω1 )V Pω2 = ω2 . Furthermore P satisfies the previous theorem. { { ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 97. ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 98. ? THFD THFD HFD HFDwω HFD HFDwω HFDw HFDw ω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 99. THFD THFD THFD HFD HFDw HFD ω HFD HFDw ω ω HFDw ? HFDw HFDw ω S-spaceω O-space S-space ω O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 100. THFD THFD THFD HFD HFDw HFD ω HFD HFDw ω ω HFDw HFDw HFDw HFDw ω ω O-space S-space ω O-space S-space O-space S-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 101. OPEN QUESTIONS ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 102. OPEN QUESTIONS Consistency questions: ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 103. OPEN QUESTIONS Consistency questions: HFD HFDwω HFDw ω O-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 104. OPEN QUESTIONS Consistency questions: HFD HFDw HFD HFDw ω ω HFDw HFDw ω ω O-space S-space O-space S-space S-space S-space ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 105. OPEN QUESTIONS Consistency questions: HFD HFDw HFD HFDw ω ω HFDw HFDw ω ω O-space S-space O-space S-space S-space S-space QUESTION (JUHASZ) Does there exists a (c, →)-HFD? ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC
  • 106. REFERENCES ERIK A. ANDREJKO INDESTRUCTIBLE SPACES WITH STRONG SEPARABILITY CCC