2 citations · 2 across the 9 of their papers we have counts for
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From Matrices to Morphisms II: Examples of Computational Categories in MATLAB and Octave
Nelson Martins-Ferreira
This article develops the notion of a computational category, motivated by the observation that many mathematical structures occurring in scientific computing already admit concret…
On the zero-classes of monoid semi-congruences
M. Hoefnagel, N. Martins-Ferreira, M. Sobral
This paper studies the zero-classes of monoid semi-congruences, understood as internal reflexive relations on a monoid. Classical examples include normal submonoids, which arise as…
The Lawvere condition
Nelson Martins-Ferreira
The original Lawvere condition asserts that every reflexive graph admits a unique natural structure of internal groupoid. This property was identified by P. T. Johnstone, following…
On Naturally and Weakly Mal'tsev Categories
Nelson Martins-Ferreira
We explore a hierarchy of notions in categorical algebra: Mal'tsev categories (where every reflexive relation is symmetric); naturally Mal'tsev categories (where every reflexive gr…
Fibrations of algebras
Danel Ahman, Greta Coraglia, Davide Castelnovo +3
We study fibrations arising from indexed categories of the following form: fix two categories and a functor $F : \mathcal{A} \times \mathcal{X} \longright…
Unitary magma actions
Nelson Martins-Ferreira
We introduce a novel concept of action for unitary magmas, facilitating the classification of various split extensions within this algebraic structure. Our method expands upon the…
On categories with arbitrary 2-cell structures
Nelson Martins-Ferreira
When a category is equipped with a 2-cell structure it becomes a sesquicategory but not necessarily a 2-category. It is widely accepted that the latter property is equivalent to th…
A syntactic characterization of weakly Mal'tsev varieties
Nadja Egner, Pierre-Alain Jacqmin, Nelson Martins-Ferreira
The notion of a weakly Mal'tsev category, as it was introduced in 2008 by the third author, is a generalization of the classical notion of a Mal'tsev category. It is well-known tha…
From A-spaces to arbitrary spaces via spatial fibrous preorders
N. Martins-Ferreira
The well known equivalence between preorders and Alexandrov spaces is extended to an equivalence between arbitrary topological spaces and spatial fibrous preorders, a new notion to…