Results 41 to 50 of about 402 (157)
Computing metric hulls in graphs [PDF]
Discrete Mathematics & Theoretical Computer Science, 2019 We prove that, given a closure function the smallest preimage of a closed set can be calculated in polynomial time in the number of closed sets. This implies that there is a polynomial time algorithm to compute the convex hull number of a graph, when all
Kolja Knauer, Nicolas Nisse
doaj +1 more source
Approximation Relations on the Posets of Pseudoultrametrics
Axioms, 2023 In this paper we study pseudoultrametrics, which are a natural mixture of ultrametrics and pseudometrics. They satisfy a stronger form of the triangle inequality than usual pseudometrics and naturally arise in problems of classification and recognition ...
Svyatoslav Nykorovych +2 more
doaj +1 more source
Signed Projective Cubes, a Homomorphism Point of View
Journal of Graph Theory, Volume 113, Issue 1, Page 38-56, September 2026.ABSTRACT The (signed) projective cubes, as a special class of graphs closely related to the hypercubes, are on the crossroad of geometry, algebra, discrete mathematics and linear algebra. Defined as Cayley graphs on binary groups, they represent basic linear dependencies.
Meirun Chen +2 more
wiley +1 more source
A characterization of a pomonoid $S$ all of its cyclic $S$-posets are regular injective [PDF]
Categories and General Algebraic Structures with Applications, 2013 This work is devoted to give a charcaterization of a pomonoid $S$ such that all cyclic $S$-posets are regular injective.
Xia Zhang, Wenling Zhang, Ulrich Knauer
doaj
Localization sequences for logarithmic topological cyclic homology
Journal of Topology, Volume 19, Issue 3, September 2026.Abstract We introduce the notion of an Ek$\mathbb {E}_k$‐ring with prelogarithmic structure, define logarithmic topological Hochschild homology and logarithmic topological cyclic homology in this context, and establish localization sequences for these theories. Our approach is based on Thom R$R$‐algebras.
John Rognes +2 more
wiley +1 more source
How to see the forest despite the trees
Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.Abstract One of the major starting points of discrete optimization is the theorem of Nash‐Williams and Tutte on the existence of k$k$ disjoint spanning trees of a graph, along with its counterpart on the existence of k$k$ forests covering all edges of the graph.
Erika Bérczi‐Kovács, András Frank
wiley +1 more source
Tate modules as condensed modules
Bulletin of the London Mathematical Society, Volume 58, Issue 7, July 2026.Abstract We prove that the category of countable Tate modules over an arbitrary discrete ring embeds fully faithfully into that of condensed modules. If the base ring is of finite type, we characterize the essential image as generated by the free module of infinite countable rank under direct sums, duals and retracts.
Valerio Melani +2 more
wiley +1 more source
On the theories classified by an étendue
Bulletin of the London Mathematical Society, Volume 58, Issue 7, July 2026.Abstract We give a model‐theoretic characterisation of the geometric theories classified by étendues—the ‘locally localic’ topoi. They are the theories where each model is determined, syntactically and semantically, by any witness of a fixed collection of formulae.
Joshua L. Wrigley
wiley +1 more source
Journal of the London Mathematical Society, Volume 114, Issue 1, July 2026.Abstract Dedekind's problem, dating back to 1897, asks for the total number ψ(n)$\psi (n)$ of antichains contained in the Boolean lattice Bn$B_n$ on n$n$ elements. We study Dedekind's problem using a recently developed method based on the cluster expansion from statistical physics, and as a result, obtain several new results on the number and typical ...
Matthew Jenssen +2 more
wiley +1 more source
On categorical aspects of S -quantales
Open Mathematics, 2018 S-quantales are characterized as injective objects in the category of S-posets with respect to certain class of homomorphisms that are order-preserving mappings. This paper is devoted to exhibitions of categorical structures on S-quantales.
Zhang Xia, Zhou Yunyan
doaj +1 more source