Fibered aspects of Yoneda's regular span

Autor: Enrico Vitale, Sandra Mantovani, Alan S. Cigoli, Giuseppe Metere
Přispěvatelé: UCL - SST/IRMP - Institut de recherche en mathématique et physique, Cigoli A.S., Mantovani S., Metere G., Vitale E.M.
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Advances in Mathematics, Vol. 360, p. 106899 (2020)
Popis: In this paper we start by pointing out that Yoneda's notion of a regular span $S \colon \mathcal{X} \to \mathcal{A} \times \mathcal{B}$ can be interpreted as a special kind of morphism, that we call fiberwise opfibration, in the 2-category $\mathsf{Fib}(\mathcal{A})$. We study the relationship between these notions and those of internal opfibration and two-sided fibration. This fibrational point of view makes it possible to interpret Yoneda's Classification Theorem given in his 1960 paper as the result of a canonical factorization, and to extend it to a non-symmetric situation, where the fibration given by the product projection $Pr_0 \colon \mathcal{A} \times \mathcal{B} \to \mathcal{A}$ is replaced by any split fibration over $\mathcal{A}$. This new setting allows us to transfer Yoneda's theory of extensions to the non-additive analog given by crossed extensions for the cases of groups and other algebraic structures.
Databáze: OpenAIRE