
Authors:
Dolph ULRICH
Title:On the independence of B from I, C, W, K'_{1} and Karpenko's formula X
Pages:9697
File:bibtex
Abstract ( + )
[Abstract]

Authors:
Jacek MALINOWSKI
Title:Some theorems on equivalential tense logic
Pages:98103
File:bibtex
Abstract ( + )
[Abstract]

Authors:
Takahito AOTO and Hiroakira ONO
Title:Nonuniqueness of normal proofs for minimal formulas in implicationconjunction fragment of BCK
Pages:104112
File:bibtex
Abstract ( + )
A minimal formula of a given logic L isa formula which is provable in L and is not a nontrivial substitution instanceof other provable formulas in L. Y. Komori asked whethernormal proofs of minimal formulas are unique in the implicational fragments ofnatural deduction systems for the intuitionistic logic and the logic BCK. It was already shown that the answer is positive for BCK, while it is negative for the intuitionistic logic. The present paper shows normal proofs for minimal formulas are not necessarily unique for the implicationconjunction fragment of BCK. This result contradicts sharply with the uniqueness of normal proofs of balanced formulas in theimplicationconjunction fragment of the intuitionistic logic.

Authors:
Marek MAGDZIAK
Title:Truth as an object
Pages:113117
File:bibtex
Abstract ( + )
By semantic theory of truth, we mean an approach in which the notion of truth is characterized by means of an expression chosen from a given language of interpretation. The material adequacy of the notion is grounded in some semantic interpretation of the language. The most influential contemporary theories  those of ScottAczel and KripkeGilmoreFeferman concern themselves with the truth predicate and its interpretation (extension and antiextension) and employ an inductive construction in the development of models. These approaches assume that truth is a property of sentences (or rather of propositions expressed by sentences). Alternatively we will consider truth as an individual object t, as an extension of an individual name t from the language. As a consequence we assume that a valuation can be partly (weakly) rendered in the language by twoplaced formula V(x,y).

Authors:
Igor URBAS
Title:A note on "Carnot's logic"
Pages:118125
File:bibtex
Abstract ( + )
[Abstract]

Authors:
Alexander S. KARPENKO
Title:Sheffer's stroke for prime numbers
Pages:126129
File:bibtex
Abstract ( + )
[Abstract]

Authors:
Jacek GEISLER and Marek NOWAK
Title:Conditional negation on the positive logic
Pages:130136
File:bibtex
Abstract ( + )
In the paper a paraconsistent logic is considered, representative of a class of sentential logics which, taking into account their features, can be called the class of classical paraconsistent logics. The truth conditions for negation in the framesemantics adequate for that logic are expressed in a conditional way.