Results 41 to 50 of about 990 (221)

Algebraic singular functions are not always dense in the ideal of C∗$C^*$‐singular functions

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract We give the first examples of étale (non‐Hausdorff) groupoids G$\mathcal {G}$ whose C∗$C^*$‐algebras contain singular elements that cannot be approximated by singular elements in Cc(G)$\mathcal {C}_c(\mathcal {G})$. We provide two examples: one is a bundle of groups and the other a minimal and effective groupoid constructed from a self‐similar
Diego Martínez, Nóra Szakács
wiley   +1 more source

A note on quasi R*-invariant measures on semigroups

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1990
A characterization of quasi r*-invariant measures on metric topological semigroups is obtained by showing that their support has a left group structure thus generalizing previously known results for relatively r*-invariant measures and the topo-algebraic
N. A. Tserpes
doaj   +1 more source

Existence of viscosity solutions to abstract Cauchy problems via nonlinear semigroups

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract In this work, we provide conditions for nonlinear monotone semigroups on locally convex vector lattices to give rise to a generalized notion of viscosity solutions to a related nonlinear partial differential equation. The semigroup needs to satisfy a convexity estimate, so called K$K$‐convexity, with respect to another family of operators ...
Fabian Fuchs, Max Nendel
wiley   +1 more source

THE DUALITY OF THE L?-REPRESENTATION ALGEBRA ?(S ) OF A FOUNDATION SEMIGROUP S AND FUNCTION ALGEBRAS [PDF]

open access: yesJournal of Sciences, Islamic Republic of Iran, 2000
In the present paper for a large family of topological semigroups, namely foundation semigroups, for which topological groups and discrete semigroups are elementary examples, it is shown that ?(S) is the dual of a function algebra.
doaj  

Excursion theory for Markov processes indexed by Lévy trees

open access: yesProceedings of the London Mathematical Society, Volume 132, Issue 5, May 2026.
Abstract We develop an excursion theory that describes the evolution of a Markov process indexed by a Lévy tree away from a regular and instantaneous point x$x$ of the state space. The theory builds upon a notion of local time at x$x$ that was recently introduced in the companion paper [Probab. Theory Related Fields. 189 (2024), 1–99].
Armand Riera, Alejandro Rosales‐Ortiz
wiley   +1 more source

Homotopy extension property in homotopy theory for topological semigroups. [PDF]

open access: yes, 2012
The purpose of this paper is to extend the concept of homotopy extension property in homotopy theory for topological spaces to its analogical structure in homotopy theory for topological semigroups.
Kilicman, Adem, Saif, Amin
core   +1 more source

(L)-Semigroup Sums

open access: yesAxioms, 2018
An (L)-semigroup S is a compact n-manifold with connected boundary B together with a monoid structure on S such that B is a subsemigroup of S. The sum S + T of two (L)-semigroups S and T having boundary B is the quotient space obtained from the ...
John R. Martin
doaj   +1 more source

The Global Glimm Property for C*‐algebras of topological dimension zero

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 4, April 2026.
Abstract We show that a C∗$C^*$‐algebra with topological dimension zero has the Global Glimm Property (every hereditary subalgebra contains an almost full nilpotent element) if and only if it is nowhere scattered (no hereditary subalgebra admits a finite‐dimensional representation). This solves the Global Glimm Problem in this setting.
Ping Wong Ng   +2 more
wiley   +1 more source

On L-Fuzzy Topological Semigroups

open access: yesJournal of Mathematical Analysis and Applications, 1993
With \(L\) as a complete Heyting algebra, \(\mu: X\to L\) an \(L\)-fuzzy subset of \(X\), the author has defined \(L\)-fuzzy topological space \((X,\mu,F)\) where \(F\subset L^ x\) satisfies some given conditions; he has defined the category FTOP by the collection of all \(L\)-fuzzy topological spaces with suitably defined morphisms. In a category \(C\)
openaire   +2 more sources

Noncommutative polygonal cluster algebras

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 4, April 2026.
Abstract We define a new family of noncommutative generalizations of cluster algebras called polygonal cluster algebras. These algebras generalize the noncommutative surfaces of Berenstein–Retakh, and are inspired by the emerging theory of Θ$\Theta$‐positivity for the groups Spin(p,q)$\mathrm{Spin}(p,q)$.
Zachary Greenberg   +3 more
wiley   +1 more source

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