E ∗-dense E-semigroupsSpringer Science and Business Media LLC - Tập 89 - Trang 105-124 - 2014
John Fountain, Anthony Hayes
We obtain a covering theorem for E
∗-dense E-semigroups showing that such a semigroup has an E
∗-dense, strongly E
∗-unitary E-semigroup as a cover and describe the structure of the latter semigroups.
On semigroup presentations that define a groupSpringer Science and Business Media LLC - Tập 90 - Trang 149-154 - 2014
G. Ayık, B. Özer
We consider the finite semigroup presentations of the form
$$\begin{aligned} \mathcal {P}=\langle a_1,\cdots ,a_n\mid w_1=a_1,\cdots ,w_n=a_n \rangle \end{aligned}$$
and their Adian graphs. It is known that if both Adian graphs of
...... hiện toàn bộ
On a Perturbation Theorem of Kaiser and WeisSpringer Science and Business Media LLC - Tập 70 - Trang 471-474 - 2005
Charles J. K. Batty
We improve a perturbation theorem of C. Kaiser and L. Weis
for semigroups of operators on Hilbert spaces by using a generation
theorem of A.M. Gomilko, D.H. Shi and D.X. Feng.
Group closures of partial transformationsSpringer Science and Business Media LLC - Tập 65 - Trang 301-313 - 2001
Inessa Levi, Japheth Wood
Let \(X\) be an infinite set, \(f\) a partial one-to-one transformation of \(X\), and \(H\) a normal subgroup of G
X
, the group of all permutations of \(X\). We investigate when \(H\) is equal to \(G_{}\). That is, we are interested when \(H\) is the full group of normalizers of the semigroup of transformations on \(X\) generated by conjugates of \(f\) by e...... hiện toàn bộ
On exposed semigroup homomophinsSpringer Science and Business Media LLC - Tập 13 - Trang 189-204 - 1976
Benno Fuchssteiner
In the main theorem of this paper the existence of weakly exposed semigroup homomorphisms is proved. This theorem is effectively equivalent to the axiom of choice and generalizes some well known theorems of functional analysis like the Hahn-Banach theorem, the Krein-Milman theorem, Bauer's minimum principle and a result of T. Husain and I. Tweddle.
A Semilinear Structure on Semigroups in a Metric SpaceSpringer Science and Business Media LLC - Tập 68 - Trang 419-444 - 2004
Rinaldo M. Colombo, Andrea Corli
We introduce a sort of semilinear structure on subsets of the family of semigroups
defined on a metric space. The key step is the definition of the sum of two
semigroups, which is here achieved by means of the classical operator splitting
technique. No linearity assumption is required, since the whole construction is
in a metric space.