http://dspace.nbuv.gov.ua:80/handle/123456789/150346 2026-04-22T14:32:33Z 2026-04-22T14:32:33Z Bondarenko, V.V. http://dspace.nbuv.gov.ua:80/handle/123456789/157398 2019-06-20T22:28:29Z 2007-01-01T00:00:00Z

On classification of CM modules over hypersurface singularities Bondarenko, V.V. This article is devoted to a special case of classification problem for Cohen-Macaulay modules over hypersurface singularities.

2007-01-01T00:00:00Z Chuchman, I. Gutik, O. http://dspace.nbuv.gov.ua:80/handle/123456789/157357 2019-06-20T22:27:59Z 2007-01-01T00:00:00Z

On H-closed topological semigroups and semilattices Chuchman, I.; Gutik, O. In this paper, we show that if S is an H-closed topological semigroup and e is an idempotent of S, then eSe is an H-closed topological semigroup. We give sufficient conditions on a linearly ordered topological semilattice to be H-closed. Also we prove that any H-closed locally compact topological semilattice and any H-closed topological weakly U-semilattice contain minimal idempotents. An example of a countably compact topological semilattice whose topological space is H-closed is constructed.

2007-01-01T00:00:00Z Fujita, H. Sakai, Y. Simson, D. http://dspace.nbuv.gov.ua:80/handle/123456789/157356 2019-06-20T22:27:44Z 2007-01-01T00:00:00Z

On Frobenius full matrix algebras with structure systems Fujita, H.; Sakai, Y.; Simson, D. Let n ≥ 2 be an integer. In [5] and [6], an n × n A-full matrix algebra over a field K is defined to be the set Mn(K) of all square n × n matrices with coefficients in K equipped with a multiplication defined by a structure system A, that is, an n-tuple of n × n matrices with certain properties. In [5] and [6], mainly A-full matrix algebras having (0, 1)-structure systems are studied, that is, the structure systems A such that all entries are 0 or 1. In the present paper we study A-full matrix algebras having non (0, 1)-structure systems. In particular, we study the Frobenius Afull matrix algebras. Several infinite families of such algebras with nice properties are constructed in Section 4.

2007-01-01T00:00:00Z Idris, I.M. http://dspace.nbuv.gov.ua:80/handle/123456789/157349 2019-06-20T22:29:49Z 2007-01-01T00:00:00Z

On division rings with general involution Idris, I.M. In this work we consider division rings with general involution. Properties of such division rings are investigated. General valuation of such division rings is introduced. We extend to this general notion some result on the extension of valuations.

2007-01-01T00:00:00Z