Results 21 to 30 of about 77 (63)
Free idempotent generated semigroups: The word problem and structure via gain graphs [PDF]
Israel Journal of Mathematics, 2021 Building on the previous extensive study of Yang, Gould and the present author, we provide a more precise insight into the group-theoretical ramifications of the word problem for free idempotent generated semigroups over finite biordered sets. We prove that such word problems are in fact equivalent to the problem of computing intersections of cosets of
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Every group is a maximal subgroup of a naturally occurring free idempotent generated semigroup [PDF]
Semigroup Forum, 2013 Gray and Ruskuc have shown that any group G occurs as the maximal subgroup of some free idempotent generated semigroup IG(E) on a biordered set of idempotents E, thus resolving a long standing open question. Given the group G, they make a careful choice for E and use a certain amount of well developed machinery.
Gould, Victoria, Yang, Dandan
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Free idempotent generated semigroups over bands and biordered sets with trivial products [PDF]
International Journal of Algebra and Computation, 2016 For any biordered set of idempotents [Formula: see text] there is an initial object [Formula: see text], the free idempotent generated semigroup over[Formula: see text], in the category of semigroups generated by a set of idempotents biorder-isomorphic to [Formula: see text].
Yang, Dandan +1 more
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Maximal subgroups of free idempotent generated semigroups over the full linear monoid [PDF]
Transactions of the American Mathematical Society, 2013 We show that the rank r r component of the free idempotent generated semigroup of the biordered set of the full linear ...
Dolinka, Igor, Gray, Robert D.
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Free idempotent generated semigroups over bands
, 2015 Free idempotent generated semigroups IG$(E)$, where $E$ is a biordered set, have provided a focus of recent research, the majority of the efforts concentrating on the behaviour of the maximal subgroups. Inspired by an example of Brittenham, Margolis and Meakin, several proofs have been offered that any group occurs as a maximal subgroup of some IG$(E)$,
Dandan, Yang, Gould, Victoria
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Nonstandard characterisations of tensor products and monads in the theory of ultrafilters
Mathematical Logic Quarterly, Volume 65, Issue 3, Page 347-369, October 2019., 2019 Abstract We use nonstandard methods, based on iterated hyperextensions, to develop applications to Ramsey theory of the theory of monads of ultrafilters. This is performed by studying in detail arbitrary tensor products of ultrafilters, as well as by characterising their combinatorial properties by means of their monads.
Lorenzo Luperi Baglini
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Jordan homomorphisms and T‐ideals
Journal of the London Mathematical Society, Volume 113, Issue 2, February 2026.Abstract Let A$A$ and B$B$ be associative algebras over a field F$F$ with char(F)≠2${\rm char}(F)\ne 2$. Our first main result states that if A$A$ is unital and equal to its commutator ideal, then every Jordan epimorphism φ:A→B$\varphi:A\rightarrow B$ is the sum of a homomorphism and an antihomomorphism. Our second main result concerns (not necessarily
Matej Brešar, Efim Zelmanov
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An Improved Computationally Efficient Method for Finding the Drazin Inverse
Discrete Dynamics in Nature and Society, Volume 2018, Issue 1, 2018., 2018 Drazin inverse is one of the most significant inverses in the matrix theory, where its computation is an intensive and useful task. The objective of this work is to propose a computationally effective iterative scheme for finding the Drazin inverse. The convergence is investigated analytically by applying a suitable initial matrix.
Haifa Bin Jebreen +2 more
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Finite models for positive combinatorial and exponential algebra
Bulletin of the London Mathematical Society, Volume 57, Issue 11, Page 3380-3400, November 2025.Abstract We use high girth, high chromatic number hypergraphs to show that there are finite models of the equational theory of the semiring of non‐negative integers whose equational theory has no finite axiomatisation, and show this also holds if factorial, fixed base exponentiation and operations for binomial coefficients are adjoined.
Tumadhir Alsulami, Marcel Jackson
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On Endomorphism Universality of Sparse Graph Classes
Journal 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
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