http://dspace.nbuv.gov.ua:80/handle/123456789/150379 2026-04-18T21:26:12Z 2026-04-18T21:26:12Z http://dspace.nbuv.gov.ua:80/handle/123456789/158466 2019-09-01T22:25:54Z 2013-01-01T00:00:00Z

Joseph Solomonovich Ponizovskii (1928 – 2012)

2013-01-01T00:00:00Z Zhuchok, Yu.V. http://dspace.nbuv.gov.ua:80/handle/123456789/152316 2019-06-09T22:26:07Z 2013-01-01T00:00:00Z

The monoid of endomorphisms of disconnected hypergraphs Zhuchok, Yu.V. We prove that the monoid of endomorphisms of an arbitrary disconnected hypergraph is isomorphic to a wreath product of a transformation semigroup with a certain small category. For disconnected hypergraphs we also study the structure of the monoid of strong endomorphisms and the group of automorphisms.

2013-01-01T00:00:00Z Zatorsky, R. Stefluk, S. http://dspace.nbuv.gov.ua:80/handle/123456789/152315 2019-06-09T22:26:24Z 2013-01-01T00:00:00Z

On one class of partition polynomials Zatorsky, R.; Stefluk, S. We consider relations between one class of partition polynomials, parafunctions of triangular matrices (tables), and linear recurrence relations.

2013-01-01T00:00:00Z Schwab, E.D. http://dspace.nbuv.gov.ua:80/handle/123456789/152314 2019-06-10T22:25:22Z 2013-01-01T00:00:00Z

Inverse semigroups generated by group congruences. The Möbius functions Schwab, E.D. The computation of the Möbius function of a Möbius category that arises from a combinatorial inverse semigroup has a distinctive feature. This computation is done on the field of finite posets. In the case of two combinatorial inverse semigroups, order isomorphisms between corresponding finite posets reduce the computation to one of the semigroups. Starting with a combinatorial inverse monoid and using a group congruence we construct a combinatorial inverse semigroup such that the Möbius function becomes an invariant to this construction. For illustration, we consider the multiplicative analogue of the bicyclic semigroup and the free monogenic inverse monoid.

2013-01-01T00:00:00Z