My talk at AAMAS 2020. We propose a formalism to model and reason about multi- agent systems. We allow agents to interact and commu- nicate in different modes so that they can pursue joint tasks; agents may dynamically synchronize, exchange data, adapt their behaviour, and reconfigure their com- munication interfaces. The formalism defines a local be- haviour based on shared variables and a global one based on message passing. We extend LTL to be able to reason explicitly about the intentions of the different agents and their interaction protocols. We also study the complexity of satisfiability and model-checking of this extension.

1. University of Gothenburg
Reconfigurable Interaction for MAS Modelling
Yehia Abd Alrahman
Joint work with Giuseppe Perelli and Nir Piterman

2. University of Gothenburg
Reconfigurable Interaction for MAS Modelling
Yehia Abd Alrahman
Joint work with Giuseppe Perelli and Nir Piterman

3. Y. Abd AlrahmanINTRODUCTION 2
CONTRIBUTIONS

4. Y. Abd AlrahmanINTRODUCTION 2
CONTRIBUTIONS

5. Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
The basic building block is an Agent

6. Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
The basic building block is an Agent
Agent i

7. Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Agent has a local state,
Vi
Agent i
initialised by the initial condition θi

8. Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
Interaction Interface
𝒯s
i, 𝒯r
i

9. @c
Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
A system is a collection of agents
Vj
Agent j
D
Messages transfer data and/or channel names
@c
Agents interact based on multicast
links c or a broadcast ⋆
𝒯s
i, 𝒯r
i

10. @c
Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
A system is a collection of agents
Vj
Agent j
D
@c
Agents interact based on multicast
links c or a broadcast ⋆
Senders can select the target using send guards gs
i
gs
i =
𝒯s
i, 𝒯r
i

11. @c
Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
A system is a collection of agents
Vj
Agent j
D
@c
Agents interact based on multicast
links c or a broadcast ⋆
gs
i =
Receive guards define connectivitygr
j
gr
j = c ∧
𝒯s
i, 𝒯r
i

12. @c
Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
A system is a collection of agents
Vj
Agent j
D
@c
Agents interact based on multicast
links c or a broadcast ⋆
gs
i = gr
j = c ∧
Side effects of interactions may incur reconfiguration
𝒯s
i, 𝒯r
i

13. V′j
Agent j
@a
Y. Abd AlrahmanRECIPE FORMALISM 3
THE RECIPE INTERACTION FORMALISM
Vi
Agent i
A system is a collection of agents
D
@c
Agents interact based on multicast
links c or a broadcast ⋆
gs
i = gr
j = c ∧
V′i
Side effects of interactions may incur reconfiguration
𝒯s
i, 𝒯r
i

14. Y. Abd AlrahmanRECIPE FORMALISM 4
RECIPE AS A DISCRETE SYSTEM

15. NON-BLOCKING BROADCAST
⋆
⋆
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
⋆
gs
= ∨
⋆
⋆
⋆

16. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
𝖬𝖲𝖦 = 𝖱𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝖮 = 𝟤 ∧ 𝖫𝖭𝖪 = 𝖢
𝖬𝖲𝖦 = 𝖱𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝖮 = 𝟤 ∧ 𝖫𝖭𝖪 = 𝖢
𝖬𝖲𝖦 = 𝖱𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝖮 = 𝟤 ∧ 𝖫𝖭𝖪 = 𝖢
𝖬𝖲𝖦 = 𝖱𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝖮 = 𝟤 ∧ 𝖫𝖭𝖪 = 𝖢
𝖬𝖲𝖦 = 𝖱𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝖮 = 𝟤 ∧ 𝖫𝖭𝖪 = 𝖢
⋆

17. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
⋆
@c,
@c,
@c,
@c,
@c,
@c,

18. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
⋆
The team is built incrementally
based on consensus per type
@c,
@c,
@c,
@c,
@c,
@c,

19. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
⋆
𝖬𝖲𝖦 = 𝖥𝗈𝗋𝗆 ∧ 𝖭𝖮 = 𝟣
The team is built incrementally
based on consensus per type
@c,
@c,
@c,
@c,
@c,
@c,
𝖬 𝖲 𝖦 = 𝖥 𝗈 𝗋 𝗆 ∧ 𝖭 𝖮 = 𝟣

20. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
⋆
𝖬 𝖲 𝖦 = 𝖥 𝗈 𝗋 𝗆 ∧ 𝖭 𝖮 = 𝟢
The team is built incrementally
based on consensus per type
@c,
@c,
@c,
@c,
@c,
@c,

21. NON-BLOCKING BROADCAST
⋆
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 5
gs
= ∨
⋆
⋆
The team is built incrementally
based on consensus per type
@c,
@c,
@c,
@c,
@c,

22. BLOCKING MULTICAST
@c
@c
@c
⋆
@c
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 6
gs
= φ
@c

23. BLOCKING MULTICAST
Not connected
/⊧ gr
(c)
Not Ready
/⊧ φ
⊧ φ
⊧ φ
@c
@c
@c
⋆
@c
⋆
⋆
Y. Abd AlrahmanRECIPE FORMALISM 6
gs
= φ
@c
Ready
⊧ φ

24. BLOCKING MULTICAST
Not Ready
/⊧ φ
⊧ φ
⊧ φ
@c
@c
@c
@c
Y. Abd AlrahmanRECIPE FORMALISM 6
gs
= φ
@c
Ready
⊧ φ

25. BLOCKING MULTICAST
⊧ φ
⊧ φ
⊧ φ
@c
@c
@c
@c
Y. Abd AlrahmanRECIPE FORMALISM 6
gs
= φ
@c
Ready
⊧ φ

26. BLOCKING MULTICAST
⊧ φ
⊧ φ
⊧ φ
@c
@c
@c
@c
Y. Abd AlrahmanRECIPE FORMALISM 6
gs
= φ
@c
Ready
⊧ φ
Start the assemble
protocol

27. SYSTEM DYNAMICS
Y. Abd AlrahmanRECIPE FORMALISM 7

28. HOW TO VERIFY RECIPE MODELS?
Y. Abd AlrahmanSPECIFICATION LOGIC 8

29. HOW TO VERIFY RECIPE MODELS?
Y. Abd AlrahmanSPECIFICATION LOGIC 8

30. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9

31. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9
Refer to the intention of an agent
The sender intends to interact with robots of types and
O = ⋅∃
(𝗍𝗒𝗉𝖾 = ) ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = )

32. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9
Refer to the intention of an agent
O = ⋅∃
(𝗍𝗒𝗉𝖾 = ) ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = )
φ1 := ⟨𝖼𝗁 = 𝖼⟩𝗍𝗋𝗎𝖾
Use channel c to send a msg

33. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9
Refer to the intention of an agent
O = ⋅∃
(𝗍𝗒𝗉𝖾 = ) ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = )
φ2 := ⟨𝗆𝗌𝗀 = 𝗋𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝗈 = 𝟤 ∧ O⟩𝗍𝗋𝗎𝖾
φ1 := ⟨𝖼𝗁 = 𝖼⟩𝗍𝗋𝗎𝖾
Recruit 2 robots from each type
Use channel c to send a msg

34. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9
Refer to the intention of an agent
O = ⋅∃
(𝗍𝗒𝗉𝖾 = ) ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = )
φ2 := ⟨𝗆𝗌𝗀 = 𝗋𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝗈 = 𝟤 ∧ O⟩𝗍𝗋𝗎𝖾 φ3(𝗄) := ⟨𝗆𝗌𝗀 = 𝖿𝗈𝗋𝗆 ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = 𝗄)⟩𝗍𝗋𝗎𝖾
φ1 := ⟨𝖼𝗁 = 𝖼⟩𝗍𝗋𝗎𝖾
Recruit 2 robots from each type
Use channel c to send a msg
Send a formation msg to a robot of type k

35. LTOL SPECIFICATIONS
Y. Abd AlrahmanSPECIFICATION LOGIC 9
Refer to the intention of an agent
O = ⋅∃
(𝗍𝗒𝗉𝖾 = ) ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = )
φ2 := ⟨𝗆𝗌𝗀 = 𝗋𝖾𝖼𝗋𝗎𝗂𝗍 ∧ 𝖭𝗈 = 𝟤 ∧ O⟩𝗍𝗋𝗎𝖾 φ3(𝗄) := ⟨𝗆𝗌𝗀 = 𝖿𝗈𝗋𝗆 ∧ ⋅∃
(𝗍𝗒𝗉𝖾 = 𝗄)⟩𝗍𝗋𝗎𝖾
φ1 := ⟨𝖼𝗁 = 𝖼⟩𝗍𝗋𝗎𝖾
After recruitment, 4 formation msgs are sent before robots can synchronise on their dedicated link c
Refer to the interaction protocol
Recruit 2 robots from each type
Use channel c to send a msg
Send a formation msg to a robot of type k
after have exactly two and two untilφ4 := φ2 φ3( ) φ3( ) φ1

36. COMPUTATIONAL COMPLEXITY
Y. Abd AlrahmanSPECIFICATION LOGIC 10

37. CONCLUSIONS AND FUTURE WORKS
Y. Abd AlrahmanCONCLUDING REMARKS 11

38. Y. Abd AlrahmanCONCLUDING REMARKS 12