2 citations · 2 across the 9 of their papers we have counts for
10 papers
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…
Reconstructing Classical Algebras via Ternary Operations
Jorge Fatelo, Nelson Martins-Ferreira
Although algebraic structures are frequently analyzed using unary and binary operations, they can also be effectively defined and unified through ternary operations. In this contex…
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…