Implication with possible exceptions

2001 ◽  
Vol 66 (2) ◽  
pp. 517-535
Author(s):  
Herman Jurjus ◽  
Harrie de Swart
Keyword(s):  
Propositional Logic ◽  
Modus Ponens ◽  
The Other ◽  
Classical Propositional Logic ◽  
Consequence Relation ◽  
Other Hand

AbstractWe introduce an implication-with-possible-exceptions and define validity of rules-with-possible-exceptions by means of the topological notion of a full subset. Our implication-with-possible-exceptions characterises the preferential consequence relation as axiomatized by Kraus, Lehmann and Magidor [Kraus, Lehmann, and Magidor, 1990]. The resulting inference relation is non-monotonic. On the other hand, modus ponens and the rule of monotony, as well as all other laws of classical propositional logic, are valid-up-to-possible exceptions. As a consequence, the rules of classical propositional logic do not determine the meaning of deducibility and inference as implication-without-exceptions.

scholarly journals Forward and Backward Chaining with P Systems

2014 ◽  
pp. 149-158
Author(s):  
Sergiu Ivanov ◽  
Artiom Alhazov ◽  
Vladimir Rogojin ◽  
Miguel A. Gutiérrez-Naranjo
Keyword(s):  
Computer Science ◽  
Propositional Logic ◽  
Membrane Computing ◽  
Modus Ponens ◽  
The Other ◽  
P Systems ◽  
Backward Chaining ◽  
Other Hand

One of the concepts that lie at the basis of membrane computing is the multiset rewriting rule. On the other hand, the paradigm of rules is profusely used in computer science for representing and dealing with knowledge. Therefore, establishing a “bridge” between these domains is important, for instance, by designing P systems reproducing the modus ponens-based forward and backward chaining that can be used as tools for reasoning in propositional logic. In this paper, the authors show how powerful and intuitive the formalism of membrane computing is and how it can be used to represent concepts and notions from unrelated areas.

scholarly journals Forward and Backward Chaining with P Systems

2011 ◽  
Vol 2 (2) ◽  
pp. 56-66 ◽  
Author(s):  
Sergiu Ivanov ◽  
Artiom Alhazov ◽  
Vladimir Rogojin ◽  
Miguel A. Gutiérrez-Naranjo
Keyword(s):  
Computer Science ◽  
Propositional Logic ◽  
Membrane Computing ◽  
Modus Ponens ◽  
The Other ◽  
P Systems ◽  
Backward Chaining ◽  
Other Hand

One of the concepts that lie at the basis of membrane computing is the multiset rewriting rule. On the other hand, the paradigm of rules is profusely used in computer science for representing and dealing with knowledge. Therefore, establishing a “bridge” between these domains is important, for instance, by designing P systems reproducing the modus ponens-based forward and backward chaining that can be used as tools for reasoning in propositional logic. In this paper, the authors show how powerful and intuitive the formalism of membrane computing is and how it can be used to represent concepts and notions from unrelated areas.

scholarly journals Forward and Backward Chaining with P Systems

2012 ◽  
pp. 1522-1531
Author(s):  
Sergiu Ivanov ◽  
Artiom Alhazov ◽  
Vladimir Rogojin ◽  
Miguel A. Gutiérrez-Naranjo
Keyword(s):  
Computer Science ◽  
Propositional Logic ◽  
Membrane Computing ◽  
Modus Ponens ◽  
The Other ◽  
P Systems ◽  
Backward Chaining ◽  
Other Hand

One of the concepts that lie at the basis of membrane computing is the multiset rewriting rule. On the other hand, the paradigm of rules is profusely used in computer science for representing and dealing with knowledge. Therefore, establishing a “bridge” between these domains is important, for instance, by designing P systems reproducing the modus ponens-based forward and backward chaining that can be used as tools for reasoning in propositional logic. In this paper, the authors show how powerful and intuitive the formalism of membrane computing is and how it can be used to represent concepts and notions from unrelated areas.

scholarly journals Control effects as a modality

2009 ◽  
Vol 19 (1) ◽  
pp. 17-26 ◽  
Author(s):  
HAYO THIELECKE
Keyword(s):  
Intuitionistic Logic ◽  
Classical Logic ◽  
Propositional Logic ◽  
The Other ◽  
Classical Propositional Logic ◽  
Double Negation ◽  
Other Hand

AbstractWe combine ideas from types for continuations, effect systems and monads in a very simple setting by defining a version of classical propositional logic in which double-negation elimination is combined with a modality. The modality corresponds to control effects, and it includes a form of effect masking. Erasing the modality from formulas gives classical logic. On the other hand, the logic is conservative over intuitionistic logic.

scholarly journals THE UBIQUITY OF CONSERVATIVE TRANSLATIONS

2012 ◽  
Vol 5 (4) ◽  
pp. 666-678 ◽  
Author(s):  
EMIL JEŘÁBEK
Keyword(s):  
Propositional Logic ◽  
Broad Class ◽  
Paraconsistent Logic ◽  
Lambek Calculus ◽  
Classical Propositional Logic ◽  
Consequence Relation ◽  
Deductive Systems ◽  
Nonclassical Logics ◽  
Conservative Translations

AbstractWe study the notion of conservative translation between logics introduced by (Feitosa & D’Ottaviano2001). We show that classical propositional logic (CPC) is universal in the sense that every finitary consequence relation over a countable set of formulas can be conservatively translated into CPC. The translation is computable if the consequence relation is decidable. More generally, we show that one can take instead of CPC a broad class of logics (extensions of a certain fragment of full Lambek calculus FL) including most nonclassical logics studied in the literature, hence in a sense, (almost) any two reasonable deductive systems can be conservatively translated into each other. We also provide some counterexamples, in particular the paraconsistent logic LP is not universal.

Principal type-schemes and condensed detachment

1990 ◽  
Vol 55 (1) ◽  
pp. 90-105 ◽  
Author(s):  
J. Roger Hindley ◽  
David Meredith
Keyword(s):  
Type Theory ◽  
Propositional Logic ◽  
Modus Ponens ◽  
The Other ◽  
Combinatory Logic ◽  
Minimal Amount ◽  
Principal Type ◽  
Condensed Detachment

The condensed detachment rule, or ruleD, was first proposed by Carew Meredith in the 1950's for propositional logic based on implication. It is a combination of modus ponens with a “minimal” amount of substitution. We shall give a precise detailed statement of rule D. (Some attempts in the published literature to do this have been inaccurate.)The D-completeness question for a given set of logical axioms is whether every formula deducible from the axioms by modus ponens and substitution can be deduced instead by rule D alone. Under the well-known formulae-as-types correspondence between propositional logic and combinator-based type-theory, rule D turns out to correspond exactly to an algorithm for computing principal type-schemes in combinatory logic. Using this fact, we shall show that D is complete for intuitionistic and classical implicational logic. We shall also show that D is incomplete for two weaker systems, BCK- and BCI-logic.In describing the formulae-as-types correspondence it is common to say that combinators correspond to proofs in implicational logic. But if “proofs” means “proofs by the usual rules of modus ponens and substitution”, then this is not true. It only becomes true when we say “proofs by rule D”; we shall describe the precise correspondence in Corollary 6.7.1 below.This paper is written for readers in propositional logic and in combinatory logic. Since workers in one field may not feel totally happy in the other, we include short introductions to both fields.We wish to record thanks to Martin Bunder, Adrian Rezus and the referee for helpful comments and advice.

Correspondences between gentzen and hilbert systems

2006 ◽  
Vol 71 (3) ◽  
pp. 903-957 ◽  
Author(s):  
J.G. Raftery
Keyword(s):  
The Other ◽  
Inference Rules ◽  
Consequence Relation ◽  
Formal Systems ◽  
Gentzen Systems ◽  
Other Hand

Most Gentzen systems arising in logic contain few axiom schemata and many rule schemata. Hilbert systems, on the other hand, usually contain few proper inference rules and possibly many axioms. Because of this, the two notions tend to serve different purposes. It is common for a logic to be specified in the first instance by means of a Gentzen calculus, whereupon a Hilbert-style presentation ‘for’ the logic may be sought—or vice versa. Where this has occurred, the word ‘for’ has taken on several different meanings, partly because the Gentzen separator ⇒ can be interpreted intuitively in a number of ways. Here ⇒ will be denoted less evocatively by ⊲.In this paper we aim to discuss some of the useful ways in which Gentzen and Hilbert systems may correspond to each other. Actually, we shall be concerned with the deducibility relations of the formal systems, as it is these that are susceptible to transformation in useful ways. To avoid potential confusion, we shall speak of Hilbert and Gentzen relations. By a Hilbert relation we mean any substitution-invariant consequence relation on formulas—this comes to the same thing as the deducibility relation of a set of Hilbert-style axioms and rules. By a Gentzen relation we mean the fully fledged generalization of this notion in which sequents take the place of single formulas. In the literature, Hilbert relations are often referred to as sentential logics. Gentzen relations as defined here are their exact sequential counterparts.

scholarly journals qbf2epr: A Tool for Generating EPR Formulas from QBF

10.29007/2b5d ◽  
2018 ◽  
Author(s):  
Martina Seidl ◽  
Florian Lonsing ◽  
Armin Biere
Keyword(s):  
Propositional Logic ◽  
Decision Problem ◽  
The Other ◽  
Quantified Boolean Formulas ◽  
Other Hand ◽  
Boolean Formulas ◽  
The One

We present the tool qbf2epr which translates quantified Boolean formulas (QBF) toformulas in effectively propositional logic (EPR). The decision problem of QBF is theprototypical problem for PSPACE, whereas EPR is NEXPTIME-complete. Thus QBF isembedded in a formalism, which is potentially more succinct. The motivation for this workis twofold. On the one hand, our tool generates challenging benchmarks for EPR solvers.On the other hand, we are interested in how EPR solvers perform compared to QBF solvers and if there are techniques implemented in EPR solvers which would also be valuable in QBF solvers and vice versa.

CLASSICALLY ARCHETYPAL RULES

2018 ◽  
Vol 11 (2) ◽  
pp. 279-294 ◽  
Author(s):  
TOMASZ POŁACIK ◽  
LLOYD HUMBERSTONE
Keyword(s):  
Propositional Logic ◽  
General Notion ◽  
Classical Propositional Logic ◽  
Consequence Relation

AbstractA one-premiss rule is said to be archetypal for a consequence relation when not only is the conclusion of any application of the rule a consequence (according to that relation) of the premiss, but whenever one formula has another as a consequence, these formulas are respectively equivalent to a premiss and a conclusion of some application of the rule. We are concerned here with the consequence relation of classical propositional logic and with the task of extending the above notion of archetypality to rules with more than one premiss, and providing an informative characterization of the set of rules falling under the more general notion.

New foundation of formal metamathematics

1938 ◽  
Vol 3 (1) ◽  
pp. 1-36 ◽  
Author(s):  
L. Chwistek ◽  
W. Hetper
Keyword(s):  
Ordinary Language ◽  
Modus Ponens ◽  
The Other ◽  
Other Hand

Our method is based on the same principles which we have assumed in a paper about the foundations of metamathematics which we published in collaboration with J. Herzberg some years ago. Nevertheless we have introduced some important modifications which enable us to use a very restricted preliminary language and to avoid any artificial construction.The problem of a restricted language in mathematics appears to be a very important one, as our ordinary language is really ambiguous and obscure. On the other hand there is the problem of restricting the intuitive logic to be used in our construction. We shall see that for this purpose we need only substitutions and modus ponens.If we avoided any abbreviation, we could reduce our preliminary language to propositions of the following forms:X is a theorem.If P, then Q.But we have to do with very long symbolic expressions and as there is not yet any machine to build up such expressions we must use abbreviations. For this purpose we shall use propositions of the following forms in the preliminary language:X is an expression.X is an abbreviation of Y.Any proposition which does not belong to one of our four forms will be excluded from our construction.

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