Searcharxiv⌕ Search

arXiv subjects

Giorgi Japaridze

Publications and source records attributed to Giorgi Japaridze.

At least 19 recordsLinked to original sources
arXiv2026

Do not throw out the baby: Clarithmetics as alternatives to weak arithmetics

Computability logic (CoL) provides a semantic foundation in which formulas represent interactive computational problems and validity corresponds to uniform algorithmic solvability. Building on this foundation, clarithmetics -- CoL-based axiomatic number theories -- combine the full arithmetical strength of Peano arithmetic (PA) with explicit control over computational resources. In contrast to traditional bounded arithmetic and related complexity-oriented systems, they strengthen rather than weaken PA. This paper, after briefly surveying the relevant fragment of CoL, presents the systems CLA4-CLA7 and CLA11 of clarithmetic, and outlines their soundness and completeness with respect to natural classes of time, space, and so called amplitude complexities. We argue that, by weakening PA, traditional complexity-oriented systems of arithmetic throw out the baby with the bathwater, discarding large amounts of innocent and useful arithmetical information and losing intensional flexibility essential for natural specification and program extraction. Clarithmetics avoid this loss while supporting direct extraction of optimal or near-optimal algorithms from proofs and providing strong intensional completeness properties absent from bounded arithmetic and related systems. A central message of the paper is that the argued advantages of clarithmetics deserve either acknowledgment or serious refutation from the weak-arithmetics community. To date, neither has occurred.

cs.LO↗
arXiv2024

A propositional cirquent calculus for computability logic

Cirquent calculus is a proof system with inherent ability to account for sharing subcomponents in logical expressions. Within its framework, this article constructs an axiomatization CL18 of the basic propositional fragment of computability logic the game-semantically conceived logic of computational resources and tasks. The nonlogical atoms of this fragment represent arbitrary so called static games, and the connectives of its logical vocabulary are negation and the parallel and choice versions of conjunction and disjunction. The main technical result of the article is a proof of the soundness and completeness of CL18 with respect to the semantics of computability logic.

cs.LO↗
arXiv2024

Thoughts on sub-Turing interactive computability

The article contains an outline of a possible new direction for Computability Logic (see www.csc.villanova.edu/~japaridz/CL/ ), focused on computability without infinite memory or other impossible-to-possess computational resources. The new approach would see such resources as external rather than internal to computing devices. They could or should be accounted for explicitly in the antecedents of logical formulas expressing computational problems.

cs.LO↗
arXiv2021

Cirquent calculus in a nutshell

This paper is a brief and informal presentation of cirquent calculus, a novel proof system for resource-conscious logics. As such, it is a refinement of sequent calculus with mechanisms that allow to explicitly account for the possibility of sharing of subexpressions/subresources between different expressions/resources. This is achieved by dealing with circuit-style constructs, termed cirquents, instead of formulas, sequents or other tree-like structures. The approach exhibits greater expressiveness, flexibility and efficiency compared to the more traditional proof-theoretic approaches.

cs.LO↗
arXiv2020

Fundamentals of computability logic 2020

This article is a semitutorial-style survey of computability logic. An extended online version of it is maintained at http://www.csc.villanova.edu/~japaridz/CL/ .

cs.LO↗
arXiv2019

Elementary-base cirquent calculus II: Choice quantifiers

Cirquent calculus is a novel proof theory permitting component-sharing between logical expressions. Using it, the predecessor article "Elementary-base cirquent calculus I: Parallel and choice connectives" built the sound and complete axiomatization CL16 of a propositional fragment of computability logic (see http://www.csc.villanova.edu/~japaridz/CL/ ). The atoms of the language of CL16 represent elementary, i.e., moveless, games, and the logical vocabulary consists of negation, parallel connectives and choice connectives. The present paper constructs the first-order version CL17 of CL16, also enjoying soundness and completeness. The language of CL17 augments that of CL18 by including choice quantifiers. Unlike classical predicate calculus, CL17 turns out to be decidable.

cs.LO↗
arXiv2019

Computability logic: Giving Caesar what belongs to Caesar

The present article is a brief informal survey of computability logic --- the game-semantically conceived formal theory of computational resources and tasks. This relatively young nonclassical logic is a conservative extension of classical first order logic but is much more expressive than the latter, yielding a wide range of new potential application areas. In a reasonable (even if not strict) sense the same holds for intuitionistic and linear logics, which allows us to say that CoL reconciles and unifies the three traditions of logical thought (and beyond) on the basis of its natural and "universal" game semantics. A comprehensive online survey of the subject can be found at http://www.csc.villanova.edu/~japaridz/CL/ .

cs.LO↗
arXiv2017

Elementary-base cirquent calculus I: Parallel and choice connectives

Cirquent calculus is a proof system manipulating circuit-style constructs rather than formulas. Using it, this article constructs a sound and complete axiomatization CL16 of the propositional fragment of computability logic (the game-semantically conceived logic of computational problems - see http://www.csc.villanova.edu/~japaridz/CL/ ) whose logical vocabulary consists of negation and parallel and choice connectives, and whose atoms represent elementary, i.e. moveless, games.

cs.LO↗
arXiv2016

A survey of computability logic

This article presents a survey of computability logic: its philosophy and motivations, main concepts and most significant results obtained so far. A continuously updated online version of this article is maintained at http://www.csc.villanova.edu/~japaridz/CL/ .

cs.LO↗
arXiv2016

Build your own clarithmetic II: Soundness

Clarithmetics are number theories based on computability logic (see http://www.csc.villanova.edu/~japaridz/CL/ ). Formulas of these theories represent interactive computational problems, and their "truth" is understood as existence of an algorithmic solution. Various complexity constraints on such solutions induce various versions of clarithmetic. The present paper introduces a parameterized/schematic version CLA11(P1,P2,P3,P4). By tuning the three parameters P1,P2,P3 in an essentially mechanical manner, one automatically obtains sound and complete theories with respect to a wide range of target tricomplexity classes, i.e. combinations of time (set by P3), space (set by P2) and so called amplitude (set by P1) complexities. Sound in the sense that every theorem T of the system represents an interactive number-theoretic computational problem with a solution from the given tricomplexity class and, furthermore, such a solution can be automatically extracted from a proof of T. And complete in the sense that every interactive number-theoretic problem with a solution from the given tricomplexity class is represented by some theorem of the system. Furthermore, through tuning the 4th parameter P4, at the cost of sacrificing recursive axiomatizability but not simplicity or elegance, the above extensional completeness can be strengthened to intensional completeness, according to which every formula representing a problem with a solution from the given tricomplexity class is a theorem of the system. This article is published in two parts. The previous Part I has introduced the system and proved its completeness, while the present Part II is devoted to proving soundness.

cs.LO↗
arXiv2016

Build your own clarithmetic I: Setup and completeness

Clarithmetics are number theories based on computability logic (see http://www.csc.villanova.edu/~japaridz/CL/ ). Formulas of these theories represent interactive computational problems, and their "truth" is understood as existence of an algorithmic solution. Various complexity constraints on such solutions induce various versions of clarithmetic. The present paper introduces a parameterized/schematic version CLA11(P1,P2,P3,P4). By tuning the three parameters P1,P2,P3 in an essentially mechanical manner, one automatically obtains sound and complete theories with respect to a wide range of target tricomplexity classes, i.e. combinations of time (set by P3), space (set by P2) and so called amplitude (set by P1) complexities. Sound in the sense that every theorem T of the system represents an interactive number-theoretic computational problem with a solution from the given tricomplexity class and, furthermore, such a solution can be automatically extracted from a proof of T. And complete in the sense that every interactive number-theoretic problem with a solution from the given tricomplexity class is represented by some theorem of the system. Furthermore, through tuning the 4th parameter P4, at the cost of sacrificing recursive axiomatizability but not simplicity or elegance, the above extensional completeness can be strengthened to intensional completeness, according to which every formula representing a problem with a solution from the given tricomplexity class is a theorem of the system. This article is published in two parts. The present Part I introduces the system and proves its completeness, while Part II is devoted to proving soundness.

cs.LO↗
arXiv2015

On the system CL12 of computability logic

Computability logic (see http://www.csc.villanova.edu/~japaridz/CL/) is a long-term project for redeveloping logic on the basis of a constructive game semantics, with games seen as abstract models of interactive computational problems. Among the fragments of this logic successfully axiomatized so far is CL12 --- a conservative extension of classical first-order logic, whose language augments that of classical logic with the so called choice sorts of quantifiers and connectives. This system has already found fruitful applications as a logical basis for constructive and complexity-oriented versions of Peano arithmetic, such as arithmetics for polynomial time computability, polynomial space computability, and beyond. The present paper introduces a third, indispensable complexity measure for interactive computations termed amplitude complexity, and establishes the adequacy of CL12 with respect to A-amplitude, S-space and T-time computability under certain minimal conditions on the triples (A,S,T) of function classes. This result very substantially broadens the potential application areas of CL12. The paper is self-contained, and targets readers with no prior familiarity with the subject.

cs.LO↗
arXiv2013

On resources and tasks

Essentially being an extended abstract of the author's 1998 PhD thesis, this paper introduces an extension of the language of linear logic with a semantics which treats sentences as tasks rather than true/false statements. A resource is understood as an agent capable of accomplishing the task expressed by such a sentence. It is argued that the corresponding logic can be used as a planning logic, whose advantage over the traditional comprehensive planning logics is that it avoids the representationalframe problem and significantly alleviates the inferential frame problem.

cs.LO↗
arXiv2013

Introduction to clarithmetic II

The earlier paper "Introduction to clarithmetic I" constructed an axiomatic system of arithmetic based on computability logic (see http://www.cis.upenn.edu/~giorgi/cl.html), and proved its soundness and extensional completeness with respect to polynomial time computability. The present paper elaborates three additional sound and complete systems in the same style and sense: one for polynomial space computability, one for elementary recursive time (and/or space) computability, and one for primitive recursive time (and/or space) computability.

cs.LO↗
arXiv2012

Introduction to clarithmetic III

The present paper constructs three new systems of clarithmetic (arithmetic based on computability logic --- see http://www.cis.upenn.edu/~giorgi/cl.html): CLA8, CLA9 and CLA10. System CLA8 is shown to be sound and extensionally complete with respect to PA-provably recursive time computability. This is in the sense that an arithmetical problem A has a t-time solution for some PA-provably recursive function t iff A is represented by some theorem of CLA8. System CLA9 is shown to be sound and intensionally complete with respect to constructively PA-provable computability. This is in the sense that a sentence X is a theorem of CLA9 iff, for some particular machine M, PA proves that M computes (the problem represented by) X. And system CLA10 is shown to be sound and intensionally complete with respect to not-necessarily-constructively PA-provable computability. This means that a sentence X is a theorem of CLA10 iff PA proves that X is computable, even if PA does not "know" of any particular machine M that computes X.

cs.LO↗
arXiv2012

The taming of recurrences in computability logic through cirquent calculus, Part I

This paper constructs a cirquent calculus system and proves its soundness and completeness with respect to the semantics of computability logic (see http://www.cis.upenn.edu/~giorgi/cl.html). The logical vocabulary of the system consists of negation, parallel conjunction, parallel disjunction, branching recurrence, and branching corecurrence. The article is published in two parts, with (the present) Part I containing preliminaries and a soundness proof, and (the forthcoming) Part II containing a completeness proof.

cs.LO↗
arXiv2011

Separating the basic logics of the basic recurrences

This paper shows that, even at the most basic level, the parallel, countable branching and uncountable branching recurrences of Computability Logic (see http://www.cis.upenn.edu/~giorgi/cl.html) validate different principles.

cs.LO↗