Results 61 to 70 of about 24,361 (205)
Regular Rees matrix semigroups and regular Dubreil-Jacotin semigroups [PDF]
Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics, 1981 AbstractA partially ordered semigroup S is said to be a Dubreil-Jacotin semigroup if there is an isotone homomorphism θ of S onto a partially ordered group such that {} has a greatest member. In this paper we investigate the structure of regular Dubreil-Jacotin semigroups in which the imposed partial order extends the natural partial order on the ...
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Duality for Evolutionary Equations With Applications to Null Controllability
Mathematical Methods in the Applied Sciences, Volume 49, Issue 5, Page 4144-4166, 30 March 2026.ABSTRACT We study evolutionary equations in exponentially weighted L2$$ {\mathrm{L}}^2 $$‐spaces as introduced by Picard in 2009. First, for a given evolutionary equation, we explicitly describe the ν$$ \nu $$‐adjoint system, which turns out to describe a system backwards in time. We prove well‐posedness for the ν$$ \nu $$‐adjoint system. We then apply
Andreas Buchinger, Christian Seifert
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On linear algebraic semigroups III
International Journal of Mathematics and Mathematical Sciences, 1981 Using some results on linear algebraic groups, we show that every connected linear algebraic semigroup S contains a closed, connected diagonalizable subsemigroup T with zero such that E(T) intersects each regular J-class of S.
Mohan S. Putcha
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Sandwich semigroups in locally small categories I: Foundations
, 2018 Fix (not necessarily distinct) objects $i$ and $j$ of a locally small category $S$, and write $S_{ij}$ for the set of all morphisms $i\to j$. Fix a morphism $a\in S_{ji}$, and define an operation $\star_a$ on $S_{ij}$ by $x\star_ay=xay$ for all $x,y\in ...
Dolinka, Igor +6 more
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Equivariant toric geometry and Euler–Maclaurin formulae
Communications on Pure and Applied Mathematics, Volume 79, Issue 3, Page 451-557, March 2026.Abstract We first investigate torus‐equivariant motivic characteristic classes of toric varieties, and then apply them via the equivariant Riemann–Roch formalism to prove very general Euler–Maclaurin‐type formulae for full‐dimensional simple lattice polytopes.
Sylvain E. Cappell +3 more
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Semigroup Forum, 1984 A poe-groupoid is a po-groupoid endowed with a greatest element e. The same for poe (le)-semigroups. In this short note, the author continues his study of regularity of poe-semigroups. The following result is proved: Theorem. Let S be a poe-semigroup.
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Semiclassical inequalities for Dirichlet and Neumann Laplacians on convex domains
Communications on Pure and Applied Mathematics, Volume 79, Issue 3, Page 762-822, March 2026.Abstract We are interested in inequalities that bound the Riesz means of the eigenvalues of the Dirichlet and Neumann Laplacians in terms of their semiclassical counterpart. We show that the classical inequalities of Berezin–Li–Yau and Kröger, valid for Riesz exponents γ≥1$\gamma \ge 1$, extend to certain values γ<1$\gamma <1$, provided the underlying ...
Rupert L. Frank, Simon Larson
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On Pseudo-contractibility and Ultra Central Approximate Identity of Some Semigroup Algebras
Journal of Mathematics, 2022 In this paper, we investigate the existence of an ultra central approximate identity for a Banach algebra A and its second dual A∗∗. Also, we prove that for a left cancellative regular semigroup S, ℓ1S∗∗ has an ultra central approximate identity if and ...
Amir Sahami, Seyedeh Fatemeh Shariati
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Brownian Motion With Partial Resetting Conditioned to Stay Positive
Bulletin of the London Mathematical Society, Volume 58, Issue 3, March 2026.Abstract We consider Brownian motion with partial resetting, which has recently attracted a lot of attention in physics as well as the mathematics literature. We analyze the speed of convergence of this process towards stationarity as well as its quasistationary behavior.
Martin Kolb, Achim Wübker
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Beyond regular semigroups [PDF]
Semigroup Forum, 2015 As the author writes in the abstract ``The aim of this paper is to study weakly \(U\)-regular semigroups, a wide class containing all regular semigroups and all abundant semigroups with a regular biordered set of idempotents. Here, \(U\) is a regular biordered set.'' (A notion of ``a regular biordered set'' was introduced in [\textit{K. S.
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