Results 81 to 90 of about 141,848 (276)

The α-bicyclic semigroup as a topological semigroup [PDF]

open access: yesSemigroup Forum, 1984
C. Eberhart and J. Selden showed that the only Hausdorff topology on the bicyclic semigroup which makes it a topological semigroup is the discrete topology. A related result proved in this paper is the following: Let \(W_{\alpha}\) be the \(\alpha\)-bisimple semigroup. The only locally compact Hausdorff semigroup topology on \(W_{\alpha}\) is discrete.
openaire   +2 more sources

Optimal Control Strategies and Continuous Dependence for Stochastic Hilfer Fractional Systems With Delay: A Volterra‐Fredholm Integro‐Differential Approach

open access: yesOptimal Control Applications and Methods, EarlyView.
The graphical abstract highlights our research on Sobolev Hilfer fractional Volterra‐Fredholm integro‐differential (SHFVFI) control problems for 1<ϱ<2$$ 1<\varrho <2 $$. We begin with the Hilfer fractional derivative (HFD) of order (1,2) in Sobolev type, which leads to Volterra‐Fredholm integro‐differential equations.
Marimuthu Mohan Raja   +3 more
wiley   +1 more source

Semigroup of k-bi-Ideals of a Semiring with Semilattice Additive Reduct

open access: yesDemonstratio Mathematica, 2016
We associate a semigroup B(S) to every semiring S with semilattice additive reduct, namely the semigroup of all k-bi-ideals of S; and such semirings S have been characterized by this associated semigroup B(S). A semiring S is k-regular if and only if B(S)
Bhuniya A. K., Jana K.
doaj   +1 more source

Inverse semigroup actions as groupoid actions [PDF]

open access: yes, 2011
To an inverse semigroup, we associate an étale groupoid such that its actions on topological spaces are equivalent to actions of the inverse semigroup. Both the object and the arrow space of this groupoid are non-Hausdorff. We show that this construction
Alcides Buss, R. Exel, R. Meyer
semanticscholar   +1 more source

Measure‐valued processes for energy markets

open access: yesMathematical Finance, Volume 35, Issue 2, Page 520-566, April 2025.
Abstract We introduce a framework that allows to employ (non‐negative) measure‐valued processes for energy market modeling, in particular for electricity and gas futures. Interpreting the process' spatial structure as time to maturity, we show how the Heath–Jarrow–Morton approach can be translated to this framework, thus guaranteeing arbitrage free ...
Christa Cuchiero   +3 more
wiley   +1 more source

Representation functions of additive bases for abelian semigroups

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2004
A subset of an abelian semigroup is called an asymptotic basis for the semigroup if every element of the semigroup with at most finitely many exceptions can be represented as the sum of two distinct elements of the basis.
Melvyn B. Nathanson
doaj   +1 more source

On representation of semigroups of inclusion hyperspaces

open access: yesKarpatsʹkì Matematičnì Publìkacìï, 2013
Given a group $X$ we study the algebraic structure of the compact right-topological semigroup $G(X)$ consisting of inclusion hyperspaces on $X$. This semigroup contains the semigroup $\lambda(X)$ of maximal linked systems as a closed subsemigroup.
V. M. Gavrylkiv
doaj   +1 more source

The subpower membership problem for semigroups

open access: yes, 2016
Fix a finite semigroup $S$ and let $a_1,\ldots,a_k, b$ be tuples in a direct power $S^n$. The subpower membership problem (SMP) asks whether $b$ can be generated by $a_1,\ldots,a_k$.
Bulatov, Andrei   +3 more
core   +1 more source

On Monothetic Semigroups [PDF]

open access: yesProceedings of the American Mathematical Society, 1957
By semigroup we shall mean a Hausdorff space together with a continuous associative multiplication. The study of monothetic semigroups has been initiated independently by several authors; most of the known results involve some form of compactness. We repeat here some of these known results for the sake of completeness. Among the results we establish is
openaire   +2 more sources

Dynamically Consistent Analysis of Realized Covariations in Term Structure Models

open access: yesMathematical Finance, EarlyView.
ABSTRACT In this article, we show how to analyze the covariation of bond prices nonparametrically and robustly, staying consistent with a general no‐arbitrage setting. This is, in particular, motivated by the problem of identifying the number of statistically relevant factors in the bond market under minimal conditions.
Dennis Schroers
wiley   +1 more source

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