All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 9 Next

Displaying 161 – 180 of 206

Showing per page

Representing free Boolean algebras

Alan Dow, P. Nyikos (1992)

Fundamenta Mathematicae

Partitioner algebras are defined in [2] and are natural tools for studying the properties of maximal almost disjoint families of subsets of ω. In this paper we investigate which free algebras can be represented as partitioner algebras or as subalgebras of partitioner algebras. In so doing we answer a question raised in [2] by showing that the free algebra with ℵ 1 generators is represented. It was shown in [2] that it is consistent that the free Boolean algebra of size continuum is not a subalgebra...

Residual implications and co-implications from idempotent uninorms

Daniel Ruiz, Joan Torrens (2004)

Kybernetika

This paper is devoted to the study of implication (and co-implication) functions defined from idempotent uninorms. The expression of these implications, a list of their properties, as well as some particular cases are studied. It is also characterized when these implications satisfy some additional properties specially interesting in the framework of implication functions, like contrapositive symmetry and the exchange principle.

Residuation in twist products and pseudo-Kleene posets

Ivan Chajda, Helmut Länger (2022)

Mathematica Bohemica

M. Busaniche, R. Cignoli (2014), C. Tsinakis and A. M. Wille (2006) showed that every residuated lattice induces a residuation on its full twist product. For their construction they used also lattice operations. We generalize this problem to left-residuated groupoids which need not be lattice-ordered. Hence, we cannot use the same construction for the full twist product. We present another appropriate construction which, however, does not preserve commutativity and associativity of multiplication....

Resolvability in c.c.c. generic extensions

Lajos Soukup, Adrienne Stanley (2017)

Commentationes Mathematicae Universitatis Carolinae

Every crowded space X is ω -resolvable in the c.c.c. generic extension V Fn ( | X | , 2 ) of the ground model. We investigate what we can say about λ -resolvability in c.c.c. generic extensions for λ > ω . A topological space is monotonically ω 1 -resolvable if there is a function f : X → ω 1 such that { x ∈ X : f ( x ) ≥ α } ⊂ d e n s e X for each α < ω 1 . We show that given a T 1 space X the following statements are equivalent: (1) X is ω 1 -resolvable in some c.c.c. generic extension; (2) X is monotonically ω 1 -resolvable; (3) X is ω 1 -resolvable in the Cohen-generic extension V Fn ( ω 1 , 2 ) ....

Restricted ideals and the groupability property. Tools for temporal reasoning

J. Martínez, P. Cordero, G. Gutiérrez, I. P. de Guzmán (2003)

Kybernetika

In the field of automatic proving, the study of the sets of prime implicants or implicates of a formula has proven to be very important. If we focus on non-classical logics and, in particular, on temporal logics, such study is useful even if it is restricted to the set of unitary implicants/implicates [P. Cordero, M. Enciso, and I. de Guzmán: Structure theorems for closed sets of implicates/implicants in temporal logic. (Lecture Notes in Artificial Intelligence 1695.) Springer–Verlag, Berlin 1999]....

Revealed automorphisms

Jiří Sgall, Antonín Sochor (1991)

Commentationes Mathematicae Universitatis Carolinae

We study automorphisms in the alternative set theory. We prove that fully revealed automorphisms are not closed under composition. We also construct some special automorphisms. We generalize the notion of revealment and Sd-class.

Revealments

Antonín Sochor, Petr Vopěnka (1980)

Commentationes Mathematicae Universitatis Carolinae

Reverse mathematics of some topics from algorithmic graph theory

Peter Clote, Jeffry Hirst (1998)

Fundamenta Mathematicae

This paper analyzes the proof-theoretic strength of an infinite version of several theorems from algorithmic graph theory. In particular, theorems on reachability matrices, shortest path matrices, topological sorting, and minimal spanning trees are considered.

Rich families and elementary submodels

Marek Cúth, Ondřej Kalenda (2014)

Open Mathematics

We compare two methods of proving separable reduction theorems in functional analysis - the method of rich families and the method of elementary submodels. We show that any result proved using rich families holds also when formulated with elementary submodels and the converse is true in spaces with fundamental minimal system and in spaces of density ℵ1. We do not know whether the converse is true in general. We apply our results to show that a projectional skeleton may be without loss of generality...

Currently displaying 161 – 180 of 206