Undecidable varieties with solvable word problems. II.
Undecidable varieties with solvable word problems. III (a semigroup variety).
Une Condition Finitude Pour les Semi-groupes
Uniformly synchronous codes.
Union and symmetry preserving homomorphisms of semigroups of closed relations.
Unique prime factorization in a partial semigroup of matrix-polynomials
We establish a unique factorization result into irreducibel elements in the partial semigroup of 2 × 2-matrices with entries in K[x] whose determinant is equal to 1, where K is a field, and where multiplication is defined as the usual matrix-multiplication if the degrees of the factors add up. This investigation is motivated by a result on matrices of entire functions.
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A regular hypersubstitution is a mapping which takes every -ary operation symbol to an -ary term. A variety is called regular-solid if it contains all algebras derived by regular hypersubstitutions. We determine the greatest regular-solid variety of semigroups. This result will be used to give a new proof for the equational description of the greatest solid variety of semigroups. We show that every variety of semigroups which is finitely based by hyperidentities is also finitely based by identities....
Varietal free products of bands.
Varieties generated by free completely simple semigroups.
Varieties of left distributive semigroups
Varieties preserved under wreath products.
Wreath Products and Equations in Semigroups - in Russisch
Алгебры и полугруппы с квадратичными функциями роста
Алгоритм распознавания разрешимости уравнений с одним неизвестным в полугруппах с мерой налегания определяющих слов, меньшей
Алгоритмические проблемы в многообразиях полугрупп
Алгоритмическое решение некоторых проблем в теории конечно определенных коммутативных полугрупп с сокращением
Блокирующие множества термов
Вложение полугрупп в группы и потенциальная обратимость
Вложимость рекурсивно определенных инверсных полугрупп в конечно определенные.
Группы с относительным стандартным базисом