Questions tagged [linear-logic]

Linear logic is a substructural logic proposed by Jean-Yves Girard as a refinement of classical and intuitionistic logic, joining the dualities of the former with many of the constructive properties of the latter. Ideas from linear logic have been influential in fields such as programming languages, game semantics, and quantum physics, as well as linguistics, particularly because of its emphasis on resource-boundedness, duality, and interaction.

Linear logic is a substructural logic proposed by Jean-Yves Girard as a refinement of classical and intuitionistic logic, joining the dualities of the former with many of the constructive properties of the latter. Ideas from linear logic have been influential in fields such as programming languages, game semantics, and quantum physics, as well as linguistics, particularly because of its emphasis on resource-boundedness, duality, and interaction.

Linear logic lends itself to many different presentations, explanations and intuitions. Proof-theoretically, it derives from an analysis of classical sequent calculus in which uses of (the structural rules) contraction and weakening are carefully controlled. Operationally, this means that logical deduction is no longer merely about an ever-expanding collection of persistent "truths", but also a way of manipulating resources that cannot always be duplicated or thrown away at will. In terms of simple denotational models, linear logic may be seen as refining the interpretation of intuitionistic logic by replacing cartesian (closed) categories by symmetric monoidal (closed) categories, or the interpretation of classical logic by replacing Boolean algebras by C*-algebras.

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What is the intuition behind the "par" operator in linear logic?

I'm $\DeclareMathOperator{\par}{\unicode{8523}}$ trying to wrap my mind around the $\par$ ("par") operator of linear logic. The other connectives have simple resource interpretations ($A\otimes B$ is "you have both $A$ and $B$", $A\&B$ is "you can…
hmp
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Why is it called linear logic?

Why is it called "Linear" Logic? What's linear about it?
psquid
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About Jean-Yves Girard

I am student and I'm studying linear logic. I saw a quote in a book: "I'm not a linear logician" - Jean-Yves Girard. Tokyo, April 1996. I searched on Google but I did not find the context of why he said it. What he meant by that phrase?
Laura
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What is the intuition behind the negative exponential '?' in linear logic?

The positive exponential $!$ has a very satisfying interpretation in terms of the standard resource interpretation of linear logic. Given a resource $a$, we know that $!a$ means an infinite supply of $a$. Or, stated more concretely in terms of the…
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Why don't the quantifiers split in linear logic?

Every presentation of linear logic I've seen seems to either omit or treat quantifiers as an after-thought. Even Girard says that there is "little to say" about them. However, if we view universal (existential) quantification as a generalization…
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What is the difference between intuitionistic, classical, modal and linear logic?

I am currently going through Philip Wadler's "Proposition as Types" and a passage of the introduction has struck me: Propositions as Types is a notion with breadth. It applies to a range of logics including propositional, predicate,…
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Defined negation in intuitionistic linear logic

Is it possible to define a negation in intuitionistic linear logic, the way one does in intuitionistic logic, i.e. $A^{\bot} \equiv A \multimap \mathbf{0}$ (or, as it would be written in intuitionistic logic, $\neg A \equiv A \to \bot$)? While I can…
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Linear Logic, what is it used for?

I read a lot about Linear Logic recently but I failed to find any real use to the logic. I'd like to know how and where Linear Logic could be applied. Something like lambda calculus can be clearly used as a programming language (scheme, lisp). But I…
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Representing a lambda calculus expression in $\textbf{Rel}_!$

In an invited talk in ICALP Tallinn 2024, Thomas Ehrhard and Laurent Regnier gave an overview of the differential lambda calculus. The talk is interesting and gives nice examples of how differentiation is relevant to lambda calculus. In one of the…
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Linear logic and linearly distributive categories

1. Context On page two of the introduction to their paper Weakly distributive categories on linearly distributive categories Cockett and Seely write: It turns out that these weak distributivity maps, when present coherently, are precisely the…
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Why is multiplicative disjunction called "par" in linear logic?

In linear logic multiplicative disjunction is often called par. This terminology goes back at least to Girard's seminal text Linear logic. I vaguely remember that I read that "par" is an abbreviation for "parallel“. If so, why? Does anyone know the…
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Graphical calculus for star-autonomous categories?

1. Definiton Let $(C, \otimes, I, a, l,r)$ be a (not necessarily symmetric) monoidal category. A (planar) star-autonomous structure on the monoidal category $C$ consists of an adjoint equivalence $D \dashv D’: C^{op} \xrightarrow{\sim} C$ together…
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In linear logic sequent calculus, can $\Gamma \vdash \Delta$ and $\Sigma \vdash \Pi$ be combined to get $\Gamma, \Sigma \vdash \Delta, \Pi$?

Linear logic is a certain variant of sequent calculus that does not generally allow contraction and weakening. Sequent calculus does admit the cut rule: given contexts $\Gamma$, $\Sigma$, $\Delta$, and $\Pi$, and a proposition $A$, we can make the…
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Distributive property of tensor ($\otimes$) over par (⅋) in linear logic

In the setting of linear logic, does the tensor $\otimes$ distribute over the par $⅋$? That is, is it possible to show that $$ A \otimes (B ⅋ C) \stackrel?\equiv (A \otimes B) ⅋ (A \otimes C) $$ holds? If not, what is a counterexample? The…
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De Morgan laws of linear logic

I find it stated, in all the resources I have searched, that the following De Morgan laws$$(A\otimes B)^{\perp}\equiv A^{\perp}\wp B^{\perp}\quad\quad\quad (A\text{&}B)^{\perp}\equiv A^\perp \oplus B^\perp$$$$(A\wp B)^{\perp}\equiv A^{\perp}\otimes…
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