Results 11 to 20 of about 284 (184)
The rank of a commutative semigroup [PDF]
Mathematica Bohemica, 2009 Summary: The concept of rank of a commutative cancellative semigroup is extended to all commutative semigroups \(S\) by defining \(\text{rank\,}S\) as the supremum of cardinalities of finite independent subsets of \(S\). Representing such a semigroup \(S\) as a semilattice \(Y\) of (Archimedean) components \(S_\alpha\), we prove that \(\text{rank\,}S\)
Cegarra, Antonio M., Petrich, Mario
openaire +1 more source
On the joins of semigroup varieties with the variety of commutative semigroups [PDF]
Proceedings of the American Mathematical Society, 1994 We show that the join of a variety of semigroups and the variety of all commutative semigroups is not finitely based, provided some weak conditions.
Sapir, M. V., Volkov, M. V.
openaire +3 more sources
Commutativity in Double Interchange Semigroups [PDF]
Applied Categorical Structures, 2018 25 pages, 5 figures, 27 references, comments ...
Fatemeh Bagherzadeh, Murray R. Bremner
openaire +2 more sources
Varieties of commutative semigroups [PDF]
Transactions of the American Mathematical Society, 1994 In this paper, we describe all equational theories of commutative semigroups in terms of certain well-quasi-orderings on the set of finite sequences of nonnegative integers. This description yields many old and new results on varieties of commutative semigroups.
openaire +2 more sources
On Semisimple Commutative Semigroups [PDF]
Transactions of the American Mathematical Society, 1975 This paper presents an application of radical theory to the structure of commutative semigroups via their semilattice decomposition. Maximal group congruences and semisimplicity are characterized for certain classes of commutative semigroups and
openaire +2 more sources
Constructions of positive commutative semigroups on the plane, II
International Journal of Mathematics and Mathematical Sciences, 1985 A positive semiroup is a topological semigroup containing a subsemigroup N isomorphic to the multiplicative semigroup of nonnegative real numbers, embedded as a closed subset of E2 in such a way that 1 is an identity and 0 is a zero.
Reuben W. Farley
doaj +1 more source
On commutativity of a semigroup which is a semilattice of commutative semigroups
Journal of Algebra, 1969 Let P,(G) and P,(G) be abstract properties pertaining to commutative semigroups G in the sense of Cohn [3]. P,(G) is said to be weaker than or equal to P,(G) and denoted by P,(G) 3 P,(G) if and only if, for any commutative semigroup S, P,(G) is satisfied by S (i.e., P,(S) is true) whenever P,(G) is satisfied by S.
Yoshida, Reikichi, Yamada, Miyuki
openaire +2 more sources
Journal of Mathematics, 2021 The concepts of (commutative, transitive, left exchangeable, belligerent, antisymmetric) interior GE-algebras and bordered interior GE-algebras are introduced, and their relations and properties are investigated.
Jeong-Gon Lee +3 more
doaj +1 more source
Conditions for the commutativity of semigroups [PDF]
Proceedings of the American Mathematical Society, 1976 Let S S be a semigroup. Then by a theorem of Tully [7]:
openaire +2 more sources
On the orbits of G-closure points of ultimately nonexpansive mappings
Fixed Point Theory and Applications, 2006 Let X be a closed subset of a Banach space and G an ultimately nonexpansive commutative semigroup of continuous selfmappings. If the G-closure of X is nonempty, then the closure of the orbit of any G-closure point is a commutative topological group.
Mo Tak Kiang
doaj +1 more source