Results 41 to 50 of about 82,422,466 (138)

Classification and enumeration of finite semigroups [PDF]

open access: yes, 2010
The classification of finite semigroups is difficult even for small orders because of their large number. Most finite semigroups are nilpotent of nilpotency rank 3.
Distler, Andreas
core   +2 more sources

The Perron Problem for C-Semigroups [PDF]

open access: yes, 2004
<p>Characterizations of Perron-type for the exponential stability of exponentially bounded C-semigroups are given. Also, some applications for the asymptotic behavior of the integrated semigroups are obtained.</p>
Prada, Petre   +2 more
core   +1 more source

A Linear Generalization of the Nearly Gorenstein Property, With Applications to Veronese Subalgebras

open access: yesMathematische Nachrichten, Volume 299, Issue 9, Page 2436-2451, September 2026.
ABSTRACT We study the nearly Gorenstein property for Veronese subalgebras of (semi‐)standard graded algebras. We introduce a condition (♮)$(\natural)$ for Cohen–Macaulay semi‐standard graded rings, motivated by the study of Ehrhart rings. We show that if a semi‐standard graded algebra R$ R$ satisfies (♮)$(\natural)$, then its Veronese subalgebras R(k)$
Sora Miyashita
wiley   +1 more source

Geometry of essential matrix ranges and the Smith–Ward problem for operator systems

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 9, September 2026.
Abstract A d$d$‐tuple of bounded linear selfadjoint operators acting on an infinite‐dimensional separable Hilbert space is said to have the Smith–Ward property if the identity map of the image of the operator system in the Calkin algebra has a completely positive lift.
Douglas Farenick   +2 more
wiley   +1 more source

The Bergman property for semigroups [PDF]

open access: yes, 2009
In this article, we study the Bergman property for semigroups and the associated notions of cofinality and strong cofinality. A large part of the paper is devoted to determining when the Bergman property, and the values of the cofinality and strong ...
Ruskuc, N.   +7 more
core   +1 more source

Geometric inverse semigroup theory: a note on the Milnor–Schwarz lemma for inverse monoids

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 9, September 2026.
Abstract We generalise the Milnor–Schwarz lemma to inverse monoids acting on presheaves of geodesic metric spaces. We provide two proofs of this fact: one only uses elementary techniques, inspired by the arguments for group actions on metric spaces; the other involves a version of the Vietoris–Rips complex, and builds on work of Chung–Martínez–Szakács.
Giorgio Mangioni, Francesco Tesolin
wiley   +1 more source

Presentations of inverse semigroups, their kernels and extensions [PDF]

open access: yes, 2011
"Part of this work was done while Gray was an EPSRC Postdoctoral Research Fellow at the University of St Andrews, Scotland"Let S be an inverse semigroup and let π:S→T be a surjective homomorphism with kernel K.
Ruskuc, Nik   +8 more
core   +1 more source

Cartwright–Sturmfels Hilbert schemes

open access: yesJournal of the London Mathematical Society, Volume 114, Issue 3, September 2026.
Abstract Let S$S$ be the Cox ring of a product of r$r$ projective spaces. In this paper, we study the Cartwright–Sturmfels Hilbert schemes of S$S$, which are multigraded Hilbert schemes that parameterize only radical ideals. Our main result shows that these Hilbert schemes are always smooth and irreducible if the Picard rank r$r$ is at most 2.
Ritvik Ramkumar, Alessio Sammartano
wiley   +1 more source

Equidistribution in 2‐nilpotent Polish groups and triple restricted sumsets

open access: yesJournal of the London Mathematical Society, Volume 114, Issue 3, September 2026.
Abstract The aim of this paper is to establish a Ratner‐type equidistribution theorem for orbits on homogeneous spaces associated with 2$\hskip.001pt 2$‐nilpotent locally compact Polish groups under the action of a countable discrete abelian group.
Ethan Ackelsberg, Asgar Jamneshan
wiley   +1 more source

Free semigroups of large critical exponent

open access: yesJournal of Topology, Volume 19, Issue 3, September 2026.
Abstract For a convergence group equipped with an expanding coarse‐cocycle, we construct finitely generated free subsemigroups, which we call Bishop−−Jonessemigroups$\textit{Bishop--Jones semigroups}$, of critical exponent arbitrarily close to but strictly less than the critical exponent of the ambient group.
Aleksander Skenderi
wiley   +1 more source

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