Displaying similar documents to “Generalized $F$-semigroups”

On left C - 𝒰 -liberal semigroups

Yong He, Fang Shao, Shi-qun Li, Wei Gao (2006)

Czechoslovak Mathematical Journal

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In this paper the equivalence 𝒬 ˜ U on a semigroup S in terms of a set U of idempotents in S is defined. A semigroup S is called a 𝒰 -liberal semigroup with U as the set of projections and denoted by S ( U ) if every 𝒬 ˜ U -class in it contains an element in U . A class of 𝒰 -liberal semigroups is characterized and some special cases are considered.

Subtraction semigroups

Bohdan Zelinka (1995)

Mathematica Bohemica

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A subtraction semigroup is a semigroup ( A , . , - ) with a further operation " - " added, called subtraction and satisfying certain axioms. The paper concerns a problem by B. M. Schein concerning the structure of multiplication in a subtraction semigroup.