Push Down Automata (PDA) is part of TOC (Theory of Computation) From this presentation you will get all the information related to PDA also it will help you to easily understand this topic. There is also one example. This PPT is very helpful for Computer science and Computer Engineer (B.C.A., M.C.A., B.TECH. , M.TECH.)

1. Topic :- Pushdown Automata
Name :- Ashish Duggal
Qualification :- M.C.A.

2. Pushdown Automata Introduction
 A PDA is more powerful than FA. Any language which can be acceptable by
FA can also be acceptable by PDA. PDA also accepts a class of language which
even cannot be accepted by FA. Thus PDA is much more superior to FA.
 Basically a pushdown automaton is − "Finite state machine" + "a stack"
 A pushdown automaton has three components −
an input tape,
a control unit, and
a stack with infinite size.
The stack head scans the top symbol of the stack.

3. A stack does two operations −
Push − a new symbol is added at the top.
Pop − the top symbol is read and removed.
A PDA may or may not read an input symbol, but it has to read the top of
the stack in every transition.

4. 7 Components of DPDA
 M = (Q, Σ, Γ, δ, q0, Z0, F), where
 Q — finite set of states
 Σ — finite input alphabet
 Γ — finite alphabet of pushdown symbols
 q0 ∈ Q — starting/initial state
 Z0 ∈ Γ — start symbol on the pushdown
 F ⊆ Q — set of final states
 δ — mapping Q × (Σ ∪ {ε}) × Γ → Q×Γ

5. 7 Components of NON-DPDA / NPDA
 M = (Q, Σ, Γ, δ, q0, Z0, F), where
 Q — finite set of states
 Σ — finite input alphabet
 Γ — finite alphabet of pushdown symbols
 δ —transition function -> Q × (Σ ∪ {ε}) × Γ → 2 ^(Q×Γ )
 q0 ∈ Q — starting/initial state
 Z0 ∈ Γ — start symbol on the pushdown
 F ⊆ Q — set of final states

6. Example

8. Thank You