scholarly journals Expansion trees with cut

2019 ◽  
Vol 29 (8) ◽  
pp. 1009-1029 ◽  
Author(s):  
Federico Aschieri ◽  
Stefan Hetzl ◽  
Daniel Weller
Keyword(s):  
Sequent Calculus ◽  
Higher Order ◽  
Point Of View ◽  
Compact Representation ◽  
Cut Elimination ◽  
Elimination Procedure ◽  
Herbrand’S Theorem ◽  
Syntactic Approach ◽  
Proof Nets ◽  
Herbrand's Theorem

AbstractHerbrand’s theorem is one of the most fundamental insights in logic. From the syntactic point of view, it suggests a compact representation of proofs in classical first- and higher-order logics by recording the information of which instances have been chosen for which quantifiers. This compact representation is known in the literature as Miller’s expansion tree proof. It is inherently analytic and hence corresponds to a cut-free sequent calculus proof. Recently several extensions of such proof representations to proofs with cuts have been proposed. These extensions are based on graphical formalisms similar to proof nets and are limited to prenex formulas.In this paper, we present a new syntactic approach that directly extends Miller’s expansion trees by cuts and also covers non-prenex formulas. We describe a cut-elimination procedure for our expansion trees with cut that is based on the natural reduction steps and shows that it is weakly normalizing.

Cut elimination and complexity bounds for intuitionistic epistemic logic

2020 ◽  
Vol 30 (1) ◽  
pp. 281-294
Author(s):  
Vladimir N Krupski
Keyword(s):  
Epistemic Logic ◽  
Sequent Calculus ◽  
Formal System ◽  
Point Of View ◽  
Cut Elimination ◽  
Polynomial Space ◽  
Complexity Bounds ◽  
Proof Search

Abstract The formal system of intuitionistic epistemic logic (IEL) was proposed by S. Artemov and T. Protopopescu. It provides the formal foundation for the study of knowledge from an intuitionistic point of view based on Brouwer–Heyting–Kolmogorov semantics of intuitionism. We construct a cut-free sequent calculus for IEL and establish that polynomial space is sufficient for the proof search in it. We prove that IEL is PSPACE-complete.

scholarly journals Herbrand's theorem as higher order recursion

2020 ◽  
Vol 171 (6) ◽  
pp. 102792
Author(s):  
Bahareh Afshari ◽  
Stefan Hetzl ◽  
Graham E. Leigh
Keyword(s):  
Higher Order ◽  
Herbrand’S Theorem ◽  
Herbrand's Theorem

SN and CR for free-style LKtq: linear decorations and simulation of normalization

2002 ◽  
Vol 67 (1) ◽  
pp. 162-196 ◽  
Author(s):  
Jean-Baptiste Joinet ◽  
Harold Schellinx ◽  
Lorenzo Tortora De Falco
Keyword(s):  
Classical Logic ◽  
Sequent Calculus ◽  
Linear Logic ◽  
Present Report ◽  
Point Of View ◽  
Strong Normalization ◽  
Structural Rules ◽  
Specific Combination ◽  
Proof Nets ◽  
Classical Proof

AbstractThe present report is a, somewhat lengthy, addendum to [4], where the elimination of cuts from derivations in sequent calculus for classical logic was studied ‘from the point of view of linear logic’. To that purpose a formulation of classical logic was used, that - as in linear logic - distinguishes between multiplicative and additive versions of the binary connectives.The main novelty here is the observation that this type-distinction is not essential: we can allow classical sequent derivations to use any combination of additive and multiplicative introduction rules for each of the connectives, and still have strong normalization and confluence of tq-reductions.We give a detailed description of the simulation of tq-reductions by means of reductions of the interpretation of any given classical proof as a proof net of PN2 (the system of second order proof nets for linear logic), in which moreover all connectives can be taken to be of one type, e.g., multiplicative.We finally observe that dynamically the different logical cuts, as determined by the four possible combinations of introduction rules, are independent: it is not possible to simulate them internally, i.e.. by only one specific combination, and structural rules.

Multiple conclusion linear logic: cut elimination and more

2020 ◽  
Vol 30 (1) ◽  
pp. 157-174 ◽  
Author(s):  
Harley Eades III ◽  
Valeria de Paiva
Keyword(s):  
Sequent Calculus ◽  
Linear Logic ◽  
Direct Proof ◽  
Cut Elimination ◽  
Tensor Model ◽  
Double Negation ◽  
Proof Nets ◽  
Small Change ◽  
Definition Of ◽  
Intuitionistic Linear Logic

Abstract Full intuitionistic linear logic (FILL) was first introduced by Hyland and de Paiva, and went against current beliefs that it was not possible to incorporate all of the linear connectives, e.g. tensor, par and implication, into an intuitionistic linear logic. Bierman showed that their formalization of FILL did not enjoy cut elimination as such, but Bellin proposed a small change to the definition of FILL regaining cut elimination and using proof nets. In this note we adopt Bellin’s proposed change and give a direct proof of cut elimination for the sequent calculus. Then we show that a categorical model of FILL in the basic dialectica category is also a linear/non-linear model of Benton and a full tensor model of Melliès’ and Tabareau’s tensorial logic. We give a double-negation translation of linear logic into FILL that explicitly uses par in addition to tensor. Lastly, we introduce a new library to be used in the proof assistant Agda for proving properties of dialectica categories.

VALENTINI’S CUT-ELIMINATION FOR PROVABILITY LOGIC RESOLVED

2012 ◽  
Vol 5 (2) ◽  
pp. 212-238 ◽  
Author(s):  
RAJEEV GORÉ ◽  
REVANTHA RAMANAYAKE
Keyword(s):  
Sequent Calculus ◽  
Point Of View ◽  
Cut Elimination ◽  
Provability Logic ◽  
Sequent Calculi ◽  
Original Proof ◽  
Underlying Assumption ◽  
Induction Argument ◽  
Formal Point ◽  
Explicit Rule

Valentini (1983) has presented a proof of cut-elimination for provability logic GL for a sequent calculus using sequents built from sets as opposed to multisets, thus avoiding an explicit contraction rule. From a formal point of view, it is more syntactic and satisfying to explicitly identify the applications of the contraction rule that are ‘hidden’ in proofs of cut-elimination for such sequent calculi. There is often an underlying assumption that the move to a proof of cut-elimination for sequents built from multisets is straightforward. Recently, however, it has been claimed that Valentini’s arguments to eliminate cut do not terminate when applied to a multiset formulation of the calculus with an explicit rule of contraction. The claim has led to much confusion and various authors have sought new proofs of cut-elimination for GL in a multiset setting.Here we refute this claim by placing Valentini’s arguments in a formal setting and proving cut-elimination for sequents built from multisets. The use of sequents built from multisets enables us to accurately account for the interplay between the weakening and contraction rules. Furthermore, Valentini’s original proof relies on a novel induction parameter called “width” which is computed ‘globally’. It is difficult to verify the correctness of his induction argument based on “width.” In our formulation however, verification of the induction argument is straightforward. Finally, the multiset setting also introduces a new complication in the case of contractions above cut when the cut-formula is boxed. We deal with this using a new transformation based on Valentini’s original arguments.Finally, we discuss the possibility of adapting this cut-elimination procedure to other logics axiomatizable by formulae of a syntactically similar form to the GL axiom.

scholarly journals FROM STENIUS’ CONSISTENCY PROOF TO SCHÜTTE’S CUT ELIMINATION FOR ω-ARITHMETIC

2015 ◽  
Vol 9 (1) ◽  
pp. 1-22
Author(s):  
ANNIKA SIDERS
Keyword(s):  
Cut Elimination ◽  
Consistency Proof ◽  
Reduction Condition ◽  
Problematic Case ◽  
Herbrand’S Theorem ◽  
Private Correspondence ◽  
Truth Definition ◽  
Logical Rules ◽  
Herbrand's Theorem ◽  
Deep Interest

AbstractThe book Das Interpretationsproblem der Formalisierten Zahlentheorie und ihre Formale Widerspruchsfreiheit by Erik Stenius published in 1952 contains a consistency proof for infinite ω-arithmetic based on a semantical interpretation. Despite the proof’s reference to semantics the truth definition is in fact equivalent to a syntactical derivability or reduction condition. Based on this reduction condition Stenius proves that the complexity of formulas in a derivation can be limited by the complexity of the conclusion. This independent result can also be proved by cut elimination for ω-arithmetic which was done by Schütte in 1951.In this paper we interpret the syntactic reduction in Stenius’ work as a method for cut elimination based on invertibility of the logical rules. Through this interpretation the constructivity of Stenius’ proof becomes apparent. This improvement was explicitly requested from Stenius by Paul Bernays in private correspondence (In a letter from Bernays begun on the 19th of September 1952 (Stenius & Bernays, 1951–75)). Bernays, who took a deep interest in Stenius’ manuscript, applied the described method in a proof Herbrand’s theorem. In this paper we prove Herbrand’s theorem, as an application of Stenius’ work, based on lecture notes of Bernays (Bernays, 1961). The main result completely resolves Bernays’ suggestions for improvement by eliminating references to Stenius’ semantics and by showing the constructive nature of the proof. A comparison with Schütte’s cut elimination proof shows how Stenius’ simplification of the reduction of universal cut formulas, which in Schütte’s proof requires duplication and repositioning of the cuts, shifts the problematic case of reduction to implications.

Double categories: a modular model of multiplicative linear logic

2002 ◽  
Vol 12 (4) ◽  
pp. 449-479 ◽  
Author(s):  
PAUL-ANDRÉ MELLIÈS
Keyword(s):  
Side Effects ◽  
Linear Logic ◽  
Cut Elimination ◽  
Elimination Procedure ◽  
Modular Model ◽  
Categorical Model ◽  
Double Categories ◽  
Proof Nets ◽  
Composite Module

We construct a double category [Dscr ] of proof-nets in multiplicative linear logic (MLL). Its horizontal arrows are MLL modules (subnets of well-formed nets), its vertical arrows model side-effects, and its double cells interpret the cut-elimination procedure. The categorical model is modular in the sense that every computation of a composite module (π1; π2) factors out as the separate and interacting computations of the two subcomponents π1 and π2. This enables us to trace MLL modules in the course of cut-elimination, and analyze their behaviour in time.

scholarly journals Voigt Transform and Umbral Image

2020 ◽  
Vol 25 (3) ◽  
pp. 49
Author(s):  
Silvia Licciardi ◽  
Rosa Maria Pidatella ◽  
Marcello Artioli ◽  
Giuseppe Dattoli
Keyword(s):  
Spectroscopic Studies ◽  
Higher Order ◽  
Point Of View ◽  
The Other ◽  
Pivotal Role ◽  
Umbral Calculus ◽  
Laguerre Functions ◽  
Hermite And Laguerre Functions ◽  
Higher Order Functions ◽  
Voigt Function

In this paper, we show that the use of methods of an operational nature, such as umbral calculus, allows achieving a double target: on one side, the study of the Voigt function, which plays a pivotal role in spectroscopic studies and in other applications, according to a new point of view, and on the other, the introduction of a Voigt transform and its possible use. Furthermore, by the same method, we point out that the Hermite and Laguerre functions, extension of the corresponding polynomials to negative and/or real indices, can be expressed through a definition in a straightforward and unified fashion. It is illustrated how the techniques that we are going to suggest provide an easy derivation of the relevant properties along with generalizations to higher order functions.

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