4 papers · 1 filter
Permutation group algorithms based on directed graphs
Christopher Jefferson, Markus Pfeiffer, Rebecca Waldecker +1
We introduce a new framework for solving an important class of computational problems involving finite permutation groups, which includes calculating set stabilisers, intersections…
Polynomial-time proofs that groups are hyperbolic
Derek Holt, Stephen Linton, Max Neunhoeffer +3
It is undecidable in general whether a given finitely presented group is word hyperbolic. We use the concept of pregroups, introduced by Stallings, to define a new class of van Kam…
Context-free word problem semigroups
Tara Brough, Alan J. Cain, Markus Pfeiffer
This paper studies the classes of semigoups and monoids with context-free and deterministic context-free word problem. First, some examples are exhibited to clarify the relationshi…
Constructing Majorana Representations
Markus Pfeiffer, Madeleine Whybrow
Majorana theory was introduced by A. A. Ivanov as an axiomatic framework in which to study objects related to the Monster simple group and the Griess algebra. Since its inception,…