Plongement d'un groupoïde médian dans le groupoïde multiplicatif d'un semi-anneau médian
Pointwise and global sums and negatives of translation relations.
Polynomials in idempotent commutative groupoids [Book]
Principal bundles, groupoids, and connections
We clarify in which precise sense the theory of principal bundles and the theory of groupoids are equivalent; and how this equivalence of theories, in the differentiable case, reflects itself in the theory of connections. The method used is that of synthetic differential geometry.
Products of mode varieties and algebras of subalgebras
Quandle coverings and their Galois correspondence
This article establishes the algebraic covering theory of quandles. For every connected quandle Q with base point q ∈ Q, we explicitly construct a universal covering p: (Q̃,q̃̃) → (Q,q). This in turn leads us to define the algebraic fundamental group , where Adj(Q) is the adjoint group of Q. We then establish the Galois correspondence between connected coverings of (Q,q) and subgroups of π₁(Q,q). Quandle coverings are thus formally analogous to coverings of topological spaces, and resemble Kervaire’s...
Quasigroups whose regular mappings are automorphisms
Quasitrivial groupoids and balanced identities
Quelques applications des catégories à involution aux algèbres universelles
Quelques classes de groupoïdes non-associatifs
Rectangular groupoids
Refinement Monoids, Vaught Monoids, and Boolean Algebras.
Regular involution groupoids revisited.
Remarks on tolerance algebras
Representation of undirected graphs by anticommutative conservative groupoids
The paper studies tolerances and congruences on anticommutative conservative groupoids. These groupoids can be assigned in a one-to-one way to undirected graphs.
Semigroup representations of commutative idempotent Abelian groupoids
Semigroup representations of medial groupoids
Simplicial T-complexes and crossed complexes: a non-abelian version of a theorem of Dold and Kan [Book]
Some remarks on distributive groupoids
Sous-catégories semi-pleines maximales d'une catégorie