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The Geometry of Interaction of Differential Interaction Nets Marc de Falco Institut de Math ematiques de Luminy Logic in Computer Science 08 choco Marc de Falco (IML) The GoI of Differential Nets LiCS08 1 / 22 Outline We study


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SLIDE 1

The Geometry of Interaction

  • f Differential Interaction Nets

Marc de Falco

Institut de Math´ ematiques de Luminy

Logic in Computer Science 08

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 1 / 22

choco

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SLIDE 2

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 3

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 4

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 5

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 6

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 7

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 8

Outline

We study differential interaction nets (din) : extension of linear logic [Ehrhard and Regnier, 2005], presented as formal sums of graph-like structures and rewriting, encoding resource λ-calculus and a finitary π-calculus geometry of interaction (GoI) : a special kind of semantics accounting for reduction, akin to game semantics, defined on fragments of linear logic [Girard, 1989],[Girard, 1995] We extend the path based version of GoI [Danos and Regnier, 1995], i.e. we define a proper notion of paths define a proper equational theory encoding reduction in a local and asynchronous way prove that the theory is coherent by giving a realisation prove that our encoding of path reduction is sound

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 2 / 22

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SLIDE 9

Linear Logic

Linear Logic from a calculus point of view

Linear Logic can be seen as an explicit substitution system for λ-calculus data is split between

  • ffers : arguments of application

provided as a factory producing exact copies of the same object term ! demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Mass production issues: non personalized offer, not fault-tolerant, . . . Can we replace it with craftsmanship?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 3 / 22

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SLIDE 10

Linear Logic

Linear Logic from a calculus point of view

Linear Logic can be seen as an explicit substitution system for λ-calculus data is split between

  • ffers : arguments of application

provided as a factory producing exact copies of the same object term ! demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Mass production issues: non personalized offer, not fault-tolerant, . . . Can we replace it with craftsmanship?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 3 / 22

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SLIDE 11

Linear Logic

Linear Logic from a calculus point of view

Linear Logic can be seen as an explicit substitution system for λ-calculus data is split between

  • ffers : arguments of application

provided as a factory producing exact copies of the same object term ! demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Mass production issues: non personalized offer, not fault-tolerant, . . . Can we replace it with craftsmanship?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 3 / 22

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SLIDE 12

Linear Logic

Linear Logic from a calculus point of view

Linear Logic can be seen as an explicit substitution system for λ-calculus data is split between

  • ffers : arguments of application

provided as a factory producing exact copies of the same object term ! demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Mass production issues: non personalized offer, not fault-tolerant, . . . Can we replace it with craftsmanship?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 3 / 22

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SLIDE 13

Linear Logic

Linear Logic from a calculus point of view

Linear Logic can be seen as an explicit substitution system for λ-calculus data is split between

  • ffers : arguments of application

provided as a factory producing exact copies of the same object term ! demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Mass production issues: non personalized offer, not fault-tolerant, . . . Can we replace it with craftsmanship?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 3 / 22

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SLIDE 14

Differential Linear Logic

Differential Linear Logic from a calculus point of view

Differential Linear Logic can be seen as an explicit substitution system for resource λ-calculus data is split between

  • ffers : arguments of application
  • rganized as a tree of offers

! ! ! ! !

demands : occurrences of variables

  • rganized as a tree of demands

? ? ? ? ?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 4 / 22

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SLIDE 15

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! !

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 16

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! !

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 17

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! ! par

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 18

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! ! tensor

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 19

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! ! dereliction co-dereliction

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 20

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! ! contraction co-contraction

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 21

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! ! weakening co-weakening

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 22

Differential Interaction Nets

the natural presentation of differential linear logic akin to proof-net of linear logic a special kind of interaction nets using the cells

` ⊗ ? ? ? ! ! !

with formal sums R + R′ and same number of free ports

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 5 / 22

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SLIDE 23

Differential Interaction Nets

Reduction rules

Dynamics over dins expressed by means of interaction rewriting rules presented in the economy settings but possible in both network setting (hence π-calculus) and mathematical setting (hence differential) `/⊗ : synchronisation of two trades

` ⊗ →

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 6 / 22

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SLIDE 24

Differential Interaction Nets

Reduction rules

Dynamics over dins expressed by means of interaction rewriting rules presented in the economy settings but possible in both network setting (hence π-calculus) and mathematical setting (hence differential) `/⊗ : synchronisation of two trades

` ⊗ →

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 6 / 22

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SLIDE 25

Differential Interaction Nets

Reduction rules

Dynamics over dins expressed by means of interaction rewriting rules presented in the economy settings but possible in both network setting (hence π-calculus) and mathematical setting (hence differential) `/⊗ : synchronisation of two trades

` ⊗ →

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 6 / 22

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SLIDE 26

Differential Interaction Nets

Reduction rules

?/! rules: we only present half of them, others obtained by duality dereliction/co-dereliction : offer meets demand

? ! →

contraction/co-contraction : independent routing

? ! →

! ? ! ?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 7 / 22

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SLIDE 27

Differential Interaction Nets

Reduction rules

dereliction/co-contraction : one demand for a binary offer

R ? ! → R

? ?

+

R

? ? duplication of R: global reduction rule

Goal of a GoI

Can we replace this global reduction with a lot of local sum propagations?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 8 / 22

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SLIDE 28

Differential Interaction Nets

Reduction rules

dereliction/co-contraction : one demand for a binary offer

R ? ! → R

? ?

+

R

? ? duplication of R: global reduction rule

Goal of a GoI

Can we replace this global reduction with a lot of local sum propagations?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 8 / 22

slide-29
SLIDE 29

Differential Interaction Nets

Reduction rules

dereliction/co-contraction : one demand for a binary offer

R ? ! → R

? ?

+

R

? ? duplication of R: global reduction rule

Goal of a GoI

Can we replace this global reduction with a lot of local sum propagations?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 8 / 22

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SLIDE 30

Differential Interaction Nets

Reduction rules

dereliction/co-weakening : a demand filled by a void offer crisis

? ! →

weakening/co-contraction : routing a void demand

? ! →

? ? weakening/co-weakening : void offer meets void demand

? ! →

We do not consider these rules here. We work on weak-reduction. (usual restriction used by GoI)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 9 / 22

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SLIDE 31

Differential Interaction Nets

Reduction rules

dereliction/co-weakening : a demand filled by a void offer crisis

? ! →

weakening/co-contraction : routing a void demand

? ! →

? ? weakening/co-weakening : void offer meets void demand

? ! →

We do not consider these rules here. We work on weak-reduction. (usual restriction used by GoI)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 9 / 22

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SLIDE 32

Paths in interaction nets

standard notion of path coming from the graph-like structure A B C D a reduction R → R′ extends to a reduction from P(R) → P(R′)⋆ a path can be destroyed ` ⊗ → persistent path: a path not destroyed by any chain of reduction GoI goal: find a structure S and a morphism w : P(R) → S such that ϕ persistent ⇐ ⇒ w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 10 / 22

slide-33
SLIDE 33

Paths in interaction nets

standard notion of path coming from the graph-like structure A B C D a reduction R → R′ extends to a reduction from P(R) → P(R′)⋆ a path can be destroyed ` ⊗ → persistent path: a path not destroyed by any chain of reduction GoI goal: find a structure S and a morphism w : P(R) → S such that ϕ persistent ⇐ ⇒ w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 10 / 22

slide-34
SLIDE 34

Paths in interaction nets

standard notion of path coming from the graph-like structure A B C D a reduction R → R′ extends to a reduction from P(R) → P(R′)⋆ a path can be destroyed ` ⊗ → persistent path: a path not destroyed by any chain of reduction GoI goal: find a structure S and a morphism w : P(R) → S such that ϕ persistent ⇐ ⇒ w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 10 / 22

slide-35
SLIDE 35

Paths in interaction nets

standard notion of path coming from the graph-like structure A B C D a reduction R → R′ extends to a reduction from P(R) → P(R′)⋆ a path can be destroyed ` ⊗ → persistent path: a path not destroyed by any chain of reduction GoI goal: find a structure S and a morphism w : P(R) → S such that ϕ persistent ⇐ ⇒ w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 10 / 22

slide-36
SLIDE 36

Paths in interaction nets

standard notion of path coming from the graph-like structure A B C D a reduction R → R′ extends to a reduction from P(R) → P(R′)⋆ a path can be destroyed ` ⊗ → persistent path: a path not destroyed by any chain of reduction GoI goal: find a structure S and a morphism w : P(R) → S such that ϕ persistent ⇐ ⇒ w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 10 / 22

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SLIDE 37

Paths in sums

What is a path in R + R′ ? How can we distinguish a path in one the Rs of R + R ? We need to fix an orientation: we consider sums are purely syntactical, i.e. as trees a path in a simple net is prefixed and suffixed by the branch of the tree to get a path in a net + S S′

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 11 / 22

slide-38
SLIDE 38

Paths in sums

What is a path in R + R′ ? How can we distinguish a path in one the Rs of R + R ? We need to fix an orientation: we consider sums are purely syntactical, i.e. as trees a path in a simple net is prefixed and suffixed by the branch of the tree to get a path in a net + S S′

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 11 / 22

slide-39
SLIDE 39

Paths in sums

What is a path in R + R′ ? How can we distinguish a path in one the Rs of R + R ? We need to fix an orientation: we consider sums are purely syntactical, i.e. as trees a path in a simple net is prefixed and suffixed by the branch of the tree to get a path in a net + S S′

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 11 / 22

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SLIDE 40

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . .

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

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SLIDE 41

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . .

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

slide-42
SLIDE 42

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . . ? ! ? !

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

slide-43
SLIDE 43

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . .

? ? ? ! ? ? ? !

+

? ! ? ? ? ! ? ?

+

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

slide-44
SLIDE 44

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . .

? ? ? ? ? ? ? ?

+

? ? ? ? ? ? ? ?

+ +

? ? ? ? ? ? ? ?

+

? ? ? ? ? ? ? ?

+ +

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

slide-45
SLIDE 45

Losing confluency

Everything can now be defined as intended the reduction is just no longer confluent. . .

? ? ? ? ? ? ? ?

+

? ? ? ? ? ? ? ?

+ +

? ? ? ? ? ? ? ?

+

? ? ? ? ? ? ? ?

+ +

=

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 12 / 22

slide-46
SLIDE 46

Names

We add names to track down the context of sum production we give a unique name to each (co)dereliction in a simple net, and we label the nodes of the tree we replace the sum producing rules by

? ! α →

? ? +α ? ? α α we add middle-four interchange law between +α and +β for α = β: (R1 +α R2) +β (R3 +α R4) ≡ (R1 +β R3) +α (R2 +β R4)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 13 / 22

slide-47
SLIDE 47

Names

We add names to track down the context of sum production we give a unique name to each (co)dereliction in a simple net, and we label the nodes of the tree we replace the sum producing rules by

? ! α →

? ? +α ? ? α α we add middle-four interchange law between +α and +β for α = β: (R1 +α R2) +β (R3 +α R4) ≡ (R1 +β R3) +α (R2 +β R4)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 13 / 22

slide-48
SLIDE 48

Names

We add names to track down the context of sum production we give a unique name to each (co)dereliction in a simple net, and we label the nodes of the tree we replace the sum producing rules by

? ! α →

? ? +α ? ? α α we add middle-four interchange law between +α and +β for α = β: (R1 +α R2) +β (R3 +α R4) ≡ (R1 +β R3) +α (R2 +β R4)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 13 / 22

slide-49
SLIDE 49

Names

We add names to track down the context of sum production we give a unique name to each (co)dereliction in a simple net, and we label the nodes of the tree we replace the sum producing rules by

? ! α →

? ? +α ? ? α α we add middle-four interchange law between +α and +β for α = β: (R1 +α R2) +β (R3 +α R4) ≡ (R1 +β R3) +α (R2 +β R4)

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 13 / 22

slide-50
SLIDE 50

∂L⋆

we construct an inverse monoid with zero ∂L⋆ and a weighting of path w with w(ϕϕ′) = w(ϕ′)w(ϕ) w(→) = w(←)⋆

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 14 / 22

slide-51
SLIDE 51

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-52
SLIDE 52

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-53
SLIDE 53

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-54
SLIDE 54

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,? = 1

uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-55
SLIDE 55

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,? = 1 everything collapses

uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-56
SLIDE 56

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

= eαeβ special generators: eα means no alpha uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

slide-57
SLIDE 57

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

= eαeβ special generators: eα means no alpha uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

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SLIDE 58

∂L⋆

we weight cell traversals with generators: ` ⊗ ? ? ! !

p q q p r? s? r! s! dα,? dα,! uα vα α α and relations : (p, q) and (uα, vα) like MLL : p⋆p = 1, q⋆p = 0, . . . r!, r?, s!, s? have bigebras relations : r ⋆

! s? = s?r ⋆ ! , . . .

d⋆

α,!dβ,?

= eαeβ special generators: eα means no alpha uα, vα, eα commutes with everything non-α d⋆

α,tst′ = uαd⋆ α,tu⋆ α , d⋆ α,trt′ = vαd⋆ α,tv ⋆ α where t = t′, α = β

? ! α →

? ? +α ? ? α α

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 15 / 22

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Properties

Non-triviality of ∂L⋆

Fact

∂L⋆ is non-trivial: 0 = 1

Proof.

by constructing a non-trivial realization as a operations on concrete objects: tokens made of stacks,. . .

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 16 / 22

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Properties

Soundness

Theorem

ϕ is weakly-persistent ⇐ ⇒ w(ϕ) = 0 normalizing factors: nϕ(ϕ′) =

  • α∈ϕ,α∈ϕ′

eα we have equality along weak-reduction up to normalizing factors:

Lemma (fundamental lemma)

R → R′ weakly, ϕ ∈ P(R) deformed by reduction either ϕ → ϕ′ and w(ϕ) = nϕ(ϕ′)w(ϕ′)

  • r ϕ destroyed and w(ϕ) = 0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 17 / 22

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Weights structure

We recover the Danos-Regnier ab⋆ theorem of GoI:

Theorem (αab⋆α⋆)

w(ϕ) = 0 or ∃α ∈ ∂L⋆+

a , a, b ∈ ∂L⋆+ me and w(ϕ) = αab⋆α⋆

where we distinguish two monoids: ∂L⋆+

me generated by {p, q, r, s, d}

∂L⋆+

a generated by {u, v, e}

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 18 / 22

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Normalized Execution

We consider formal sums of weights and set NEXR0(R) =

  • ϕ∈R

nR0(ϕ)w(ϕ)

Theorem

NEXR0 is an invariant of weak reductions starting from R0

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 19 / 22

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Expressive power of the equational theory

∂L⋆ is rich enough to encode more than ∂LL MLL MALL M?LL MELL ∂LL LL ∂LL!

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 20 / 22

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Expressive power of the equational theory

∂L⋆ is rich enough to encode more than ∂LL MLL MALL M?LL MELL ∂LL LL ∂LL! MLL MALL MELL M?LL ∂LL for MELL we have to extend a bit ∂L⋆, but the extension is also non-trivial

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 20 / 22

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Expressive power of the equational theory

∂L⋆ is rich enough to encode more than ∂LL MLL MALL M?LL MELL ∂LL LL ∂LL! MLL MALL MELL M?LL ∂LL LL

  • ut of reach because of the interactions between exponentials and additives

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 20 / 22

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SLIDE 66

Expressive power of the equational theory

∂L⋆ is rich enough to encode more than ∂LL MLL MALL M?LL MELL ∂LL LL ∂LL! MLL MALL MELL M?LL ∂LL ∂LL!

  • ut of reach because of the strong use of commutativity of links [Tranquilli, 2007]

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 20 / 22

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SLIDE 67

Future works

Non-deterministic computation

differential interaction nets can encode a finitary π-calculus, thus giving a notion of paths and GoI for this calculus the notion of sub-tree can be made compatible with the sum interchange law: slices the weight of slices is a lattice, thus, we can express properties of non-determinism as computations of lower and upper bounds

sharing graphs and readback process for dins AJM-style game semantics extracted from the GoI try to extend the GoI to ∂LL!, maybe by means of variants to cope with commutativity issues

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 21 / 22

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SLIDE 68

Future works

Non-deterministic computation

differential interaction nets can encode a finitary π-calculus, thus giving a notion of paths and GoI for this calculus the notion of sub-tree can be made compatible with the sum interchange law: slices the weight of slices is a lattice, thus, we can express properties of non-determinism as computations of lower and upper bounds

sharing graphs and readback process for dins AJM-style game semantics extracted from the GoI try to extend the GoI to ∂LL!, maybe by means of variants to cope with commutativity issues

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 21 / 22

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SLIDE 69

Future works

Non-deterministic computation

differential interaction nets can encode a finitary π-calculus, thus giving a notion of paths and GoI for this calculus the notion of sub-tree can be made compatible with the sum interchange law: slices the weight of slices is a lattice, thus, we can express properties of non-determinism as computations of lower and upper bounds

sharing graphs and readback process for dins AJM-style game semantics extracted from the GoI try to extend the GoI to ∂LL!, maybe by means of variants to cope with commutativity issues

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 21 / 22

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SLIDE 70

Future works

Non-deterministic computation

differential interaction nets can encode a finitary π-calculus, thus giving a notion of paths and GoI for this calculus the notion of sub-tree can be made compatible with the sum interchange law: slices the weight of slices is a lattice, thus, we can express properties of non-determinism as computations of lower and upper bounds

sharing graphs and readback process for dins AJM-style game semantics extracted from the GoI try to extend the GoI to ∂LL!, maybe by means of variants to cope with commutativity issues

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 21 / 22

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Questions

?

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 22 / 22

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beamericonarticle

Danos, V. and Regnier, L. (1995). Proof-nets and the Hilbert space. In [Girard et al., 1995].

beamericonarticle

Ehrhard, T. and Regnier, L. (2005). Uniformity and the Taylor expansion of ordinary lambda-terms. Accept´ e ` a Theoretical Computer Science, en cours de r´ evision.

beamericonarticle

Girard, J.-Y. (1989). Geometry of interaction I: an interpretation of system F. In Ferro, Bonotto, V. and Zanardo, editors, Proceedings of the Logic Colloquium 88, pages 221–260, Padova. North-Holland.

beamericonarticle

Girard, J.-Y. (1995). Geometry of interaction III: acommodating the additives. In [Girard et al., 1995].

beamericonarticle

Girard, J.-Y., Lafont, Y., and Regnier, L., editors (1995). Advances in Linear Logic, volume 222 of London Mathematical Society Lecture Note Series. Cambridge University Press.

Marc de Falco (IML) The GoI of Differential Nets LiCS’08 22 / 22