Robert D. Gray

collaborators

3 papers

math.GR2025

Twisted products of monoids

James East, Robert D. Gray, P. A. Azeef Muhammed +1

A twisting of a monoid $S$ is a map $I^¦ : S \times S \to N$ satisfying the identity $I^¦ (a, b) + I^¦ (ab, c) = I^¦ (a, b c) + I^¦ (b, c)$ . Together with an additive commutative monoid $M$ ,…

math.GR2025

Maximal subgroups of free projection- and idempotent-generated semigroups with applications to partition monoids

James East, Robert D. Gray, P. A. Azeef Muhammed +1

This paper investigates the maximal subgroups of a free projection-generated regular $*$ -semigroup $P G (P)$ over a projection algebra $P$ , and their relationship to the maximal subg…

math.RA2025

Projection algebras and free projection- and idempotent-generated regular $*$ -semigroups

James East, Robert D. Gray, P. A. Azeef Muhammed +1

The purpose of this paper is to introduce a new family of semigroups - the free projection-generated regular $*$ -semigroups - and initiate their systematic study. Such a semigroup…

Twisted products of monoids

Maximal subgroups of free projection- and idempotent-generated semigroups with applications to partition monoids

Projection algebras and free projection- and idempotent-generated regular ∗-semigroups

Projection algebras and free projection- and idempotent-generated regular $*$ -semigroups