Results 41 to 50 of about 16,532 (225)

On countably compact 0-simple topological inverse semigroups

open access: yes, 2008
We describe the structure of 0-simple countably compact topological inverse semigroups and the structure of congruence-free countably compact topological inverse ...
Gutik, Oleg, Repovš, Dušan
core   +1 more source

Acoustic waves interacting with non–locally reacting surfaces in a Lagrangian framework

open access: yesMathematische Nachrichten, Volume 298, Issue 12, Page 3855-3892, December 2025.
Abstract The paper deals with a family of evolution problems arising in the physical modeling of small amplitude acoustic phenomena occurring in a fluid, bounded by a surface of extended reaction. They are all derived in a Lagrangian framework. We study well‐posedness of these problems, their mutual relations, and their relations with other evolution ...
Enzo Vitillaro
wiley   +1 more source

Conformal optimization of eigenvalues on surfaces with symmetries

open access: yesJournal of the London Mathematical Society, Volume 112, Issue 6, December 2025.
Abstract Given a conformal action of a discrete group on a Riemann surface, we study the maximization of Laplace and Steklov eigenvalues within a conformal class, considering metrics invariant under the group action. We establish natural conditions for the existence and regularity of maximizers. Our method simplifies the previously known techniques for
Denis Vinokurov
wiley   +1 more source

Topological properties of semigroup primes of a commutative ring

open access: yes, 2017
A semigroup prime of a commutative ring $R$ is a prime ideal of the semigroup $(R,\cdot)$. One of the purposes of this paper is to study, from a topological point of view, the space $\scal(R)$ of prime semigroups of $R$.
Finocchiaro, Carmelo A.   +2 more
core   +1 more source

Is every product system concrete?

open access: yesTransactions of the London Mathematical Society, Volume 12, Issue 1, December 2025.
Abstract Is every product system of Hilbert spaces over a semigroup P$P$ concrete, that is, isomorphic to the product system of an E0$E_0$‐semigroup over P$P$? The answer is no if P$P$ is discrete, cancellative and does not embed in a group. However, we show that the answer is yes for a reasonable class of semigroups.
S. Sundar
wiley   +1 more source

Extending binary operations to funtor-spaces

open access: yesKarpatsʹkì Matematičnì Publìkacìï, 2009
Given a continuous monadic functor $T:CompoComp$ in thecategory of compacta and a discrete topological semigroup $X$ weextend the semigroup operation $varphi:Ximes Xo X$ to aright-topological semigroup operation $Phi:Teta Ximes TetaXo Teta X,$ whose ...
T. O. Banakh, V. M. Gavrylkiv
doaj  

Growth problems in diagram categories

open access: yesBulletin of the London Mathematical Society, Volume 57, Issue 11, Page 3454-3469, November 2025.
Abstract In the semisimple case, we derive (asymptotic) formulas for the growth rate of the number of summands in tensor powers of the generating object in diagram/interpolation categories.
Jonathan Gruber, Daniel Tubbenhauer
wiley   +1 more source

Recent developments around partial actions

open access: yes, 2018
We give an overview of publications on partial actions and related concepts, paying main attention to some recent developments.Comment: New bibliography added and ...
Dokuchaev, Mikhailo
core   +1 more source

On Endomorphism Universality of Sparse Graph Classes

open access: yesJournal of Graph Theory, Volume 110, Issue 2, Page 223-244, October 2025.
ABSTRACT We show that every commutative idempotent monoid (a.k.a. lattice) is the endomorphism monoid of a subcubic graph. This solves a problem of Babai and Pultr and the degree bound is best‐possible. On the other hand, we show that no class excluding a minor can have all commutative idempotent monoids among its endomorphism monoids. As a by‐product,
Kolja Knauer, Gil Puig i Surroca
wiley   +1 more source

An Application of Sombor Index over a Special Class of Semigroup Graph

open access: yesJournal of Mathematics, 2021
Recently, Gutman introduced a class of novel topological invariants named Sombor index which is defined asSOG=∑uv∈EGdu2+dv2. In this study, the Sombor index of monogenic semigroup graphs, which is an important class of algebraic structures, is calculated.
Seda Oğuz Ünal
doaj   +1 more source

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