On convexities of lattices
On coverings of random graphs
On direct decompositions of certain orthomodular lattices.
On distances and metrics in discrete ordered sets
Discrete partially ordered sets can be turned into distance spaces in several ways. The distance functions may or may not satisfy the triangle inequality and restrictions of the distance to finite chains may or may not coincide with the natural, difference-of-height distance measured in a chain. It is shown that for semilattices the semimodularity ensures the good behaviour of the distances considered. The Jordan-Dedekind chain condition, which is weaker than semimodularity, is equivalent to the...
On duality of submodule lattices
An elementary proof is given for Hutchinson's duality theorem, which states that if a lattice identity λ holds in all submodule lattices of modules over a ring R with unit element then so does the dual of λ.
On existence conditions for compatible tolerances
On extensions of measures
On free pseudo-complemented and relatively pseudo-complemented semi-lattices
On generating and concreteness in quantum logics
On Goldie absolute direct summands in modular lattices
Absolute direct summand in lattices is defined and some of its properties in modular lattices are studied. It is shown that in a certain class of modular lattices, the direct sum of two elements has absolute direct summand if and only if the elements are relatively injective. As a generalization of absolute direct summand (ADS for short), the concept of Goldie absolute direct summand in lattices is introduced and studied. It is shown that Goldie ADS property is inherited by direct summands. A necessary...
On interval decomposition lattices
Intervals in binary or n-ary relations or other discrete structures generalize the concept of interval in an ordered set. They are defined abstractly as closed sets of a closure system on a set V, satisfying certain axioms. Decompositions are partitions of V whose blocks are intervals, and they form an algebraic semimodular lattice. Lattice-theoretical properties of decompositions are explored, and connections with particular types of intervals are established.
On interval homogeneous orthomodular lattices
An orthomodular lattice is said to be interval homogeneous (resp. centrally interval homogeneous) if it is -complete and satisfies the following property: Whenever is isomorphic to an interval, , in then is isomorphic to each interval with and (resp. the same condition as above only under the assumption that all elements , , , are central in ). Let us denote by Inthom (resp. Inthom) the class of all interval homogeneous orthomodular lattices (resp. centrally interval homogeneous...
On isomorphisms of inner product spaces
On Kalmbach measurability
In this note we show that, for an arbitrary orthomodular lattice , when is a faithful, finite-valued outer measure on , then the Kalmbach measurable elements of form a Boolean subalgebra of the centre of .
On modularity in lattices of congruences on ordered sets
On projective intervals in a modular lattice
In this paper a combinatorial result concerning paire of projective intervals of a modular lattice will be established.
On quantic conuclei in orthomodular lattices.
On semimodular lattices of generating systems
On skew lattices. II.
On some properties of transformations of a logic