Results 21 to 30 of about 5,766,109 (87)
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
Identifiability of points and rigidity of hypergraphs under algebraic constraints
Journal of the London Mathematical Society, Volume 114, Issue 1, July 2026.Abstract The identifiability problem arises naturally in a number of contexts in mathematics and computer science. Specific instances include local or global rigidity of graphs and unique completability of partially‐filled tensors subject to rank conditions.
James Cruickshank +3 more
wiley +1 more source
HNN extensions and embedding theorems for groups
Journal of the London Mathematical Society, Volume 113, Issue 5, May 2026.Abstract The Higman–Neumann–Neumann (HNN) paper of 1949 is a landmark of group theory in the 20th century. The proof of its main theorem covers less than a page and uses only pre‐existing technology, but the construction that it introduced, the HNN extension, quickly became one of the principal tools of combinatorial group theory, widely used to build ...
Martin R. Bridson +1 more
wiley +1 more source
Noûs, Volume 60, Issue 1, Page 136-160, March 2026.Abstract It is well‐recognized in the sciences that a multitude of nonequivalent models are used by researchers to fulfill a range of goals, even for the same target system, a result known broadly as model pluralism. The possibility of the same form of pluralism occurring in logic, however, has not been adequately considered.
Ben Martin
wiley +1 more source
Some generalizations of Kannan's fixed point theorem in K-metric spaces [PDF]
, 2012 We extend some known fixed point results for mappings satisfying Kannan type conditions to the context of K-metric spaces. Firstly, we prove a common fixed point result for noncommuting maps.
Lorenzo Ramírez, Josefa +2 more
core +2 more sources
Simple groups with strong fixed‐point properties
Bulletin of the London Mathematical Society, Volume 58, Issue 1, January 2026.Abstract We exhibit finitely generated torsion‐free groups for which any action on any finite‐dimensional CW‐complex with finite Betti numbers has a global fixed point.
Nansen Petrosyan
wiley +1 more source
Plank theorems and their applications: A survey
Bulletin of the London Mathematical Society, Volume 58, Issue 1, January 2026.Abstract Plank problems concern the covering of convex bodies by planks in Euclidean space and are related to famous open problems in convex geometry. In this survey, we introduce plank problems and present surprising applications of plank theorems in various areas of mathematics.
William Verreault
wiley +1 more source
Noûs, Volume 59, Issue 4, Page 851-872, December 2025.Abstract A new argument is offered which proceeds through epistemic possibility (for all S knows, p), cutting a trail from modality to Millianism, the controversial thesis that the semantic content of a proper name is simply its bearer. New definitions are provided for various epistemic modal notions.
Nathan Salmón
wiley +1 more source
A new approach to the Assad-Kirk fixed point theorem
, 2016 Altun, Ishak/0000-0002-7967-0554; MINAK, GULHAN/0000-0002-3711-9633In the present paper, considering the Wardowski's technique, we give a new approach to the Assad-Kirk fixed point theorem on metrically convex metric spaces.
Olgun, Murat +2 more
core +1 more source
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
wiley +1 more source