James East

activity

20152026

most citedFinite Diagram Semigroups: Extending the Computational Horizon

5 citations · 10 across the 9 of their papers we have counts for

collaborators

Showing 2017Show all

7 papers · 1 filter

math.CO2017

Integer polygons of given perimeter

James East, Ron Niles

A classical result of Honsberger states that the number of incongruent triangles with integer sides and perimeter $n$ is the nearest integer to $\frac{n ^{2}}{48}$ ( $n$ even) or $\fra…

math.GR2017

Sandwich semigroups in locally small categories II: Transformations

Igor Dolinka, Ivana Ðurđev, James East +4

Fix sets $X$ and $Y$ , and write $P T_{X Y}$ for the set of all partial functions $X \to Y$ . Fix a partial function $a : Y \to X$ , and define the operation $⋆_{a}$ on $\mathca…

math.GR2017

Sandwich semigroups in locally small categories I: Foundations

Igor Dolinka, Ivana Đurđev, James East +4

Fix (not necessarily distinct) objects $i$ and $j$ of a locally small category $S$ , and write $S_{ij}$ for the set of all morphisms $i \to j$ . Fix a morphism $a \in S_{j i}$ , and defi…

math.GR2017

Idempotents and one-sided units in infinite partial Brauer monoids

James East

We study monoids generated by various combinations of idempotents and one- or two-sided units of an infinite partial Brauer monoid. This yields a total of eight such monoids, each…

math.GR2017

Congruence lattices of finite diagram monoids

James East, James D. Mitchell, Nik Ruskuc +1

We give a complete description of the congruence lattices of the following finite diagram monoids: the partition monoid, the planar partition monoid, the Brauer monoid, the Jones m…

math.GR2017

Maximal subsemigroups of finite transformation and diagram monoids

James East, Jitender Kumar, James D. Mitchell +1

We describe and count the maximal subsemigroups of many well-known monoids of transformations and monoids of partitions. More precisely, we find the maximal subsemigroups of the fu…