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The axioms for implication in orthologic

Ivan Chajda (2008)

Czechoslovak Mathematical Journal

We set up axioms characterizing logical connective implication in a logic derived by an ortholattice. It is a natural generalization of an orthoimplication algebra given by J. C. Abbott for a logic derived by an orthomodular lattice.

The Bordalo order on a commutative ring

Melvin Henriksen, Frank A. Smith (1999)

Commentationes Mathematicae Universitatis Carolinae

If R is a commutative ring with identity and is defined by letting a b mean a b = a or a = b , then ( R , ) is a partially ordered ring. Necessary and sufficient conditions on R are given for ( R , ) to be a lattice, and conditions are given for it to be modular or distributive. The results are applied to the rings Z n of integers mod n for n 2 . In particular, if R is reduced, then ( R , ) is a lattice iff R is a weak Baer ring, and ( R , ) is a distributive lattice iff R is a Boolean ring, Z 3 , Z 4 , Z 2 [ x ] / x 2 Z 2 [ x ] , or a four element field.

The Bruhat rank of a binary symmetric staircase pattern

Zhibin Du, Carlos M. da Fonseca (2016)

Open Mathematics

In this work we show that the Bruhat rank of a symmetric (0,1)-matrix of order n with a staircase pattern, total support, and containing In, is at most 2. Several other related questions are also discussed. Some illustrative examples are presented.

The category of compactifications and its coreflections

Anthony W. Hager, Brian Wynne (2022)

Commentationes Mathematicae Universitatis Carolinae

We define “the category of compactifications”, which is denoted CM, and consider its family of coreflections, denoted corCM. We show that corCM is a complete lattice with bottom the identity and top an interpretation of the Čech–Stone β . A c corCM implies the assignment to each locally compact, noncompact Y a compactification minimum for membership in the “object-range” of c . We describe the minimum proper compactifications of locally compact, noncompact spaces, show that these generate the atoms...

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