3 papers
math.CT2026
Observations on the variety of equationally linear Heyting semilattices
Xabier García-Martínez, James R. A. Gray, Michael A. Hoefnagel +2
In previous work, we analysed a number of categorical properties, of interest in the context of Janelidze-Márki-Tholen semi-abelian categories, for the variety of…
math.CT2025
Categorical-algebraic aspects of Heyting semilattices
Xabier García-Martínez, James R. A. Gray, Michael A. Hoefnagel +2
This article gives an overview of some key categorical-algebraic properties of the variety of Heyting semilattices, with the aim of correcting a misconception in the literature. We…
math.CT2025
Nice exact categories are coexact
James Richard Andrew Gray
Several important types of categories have been shown to be both exact and coexact (in the sense of Barr). The first type consists of abelian categories, which due to their self-du…