This paper describes the notion of a (latent) factorization system for a restriction category. Analogous to factorization systems for ordinary categories, a description in terms of a Galois connection based on an orthogonality relation is given. The orthogonality relation involving a unique cross-map (or lifting), however, is between a pair, consisting of a map together with a restriction idempotent, and a map. This gives a significantly different character to the theory.
A restriction category in which the idempotents split is precisely a partial map category whose partiality is given by the system of monics which split the restriction idempotents. A restriction factorization on such a partial map category is completely characterized by a factorization on the total maps which is stable with respect to the system of monics; that is, pullbacks of both E and M-maps along these special monics are (respectively) E and M-maps.
Examples of latent factorization systems are discussed. In particular, one source of latent factorizations is provided by lifting latent factorizations from the base of a latent fibration into the total category: this is a generalization of the observation that one can lift a factorization from the base of an ordinary fibration into the total category.
Keywords: Restriction categories, Factorization Systems
@article{TAC_2024_42_a6,
author = {Robin Cockett and G.S.H. Cruttwell and Jonathan Gallagher and Dorette Pronk},
title = {Factorization {Systems} for {Restriction} {Categories}},
journal = {Theory and applications of categories},
pages = {145--171},
year = {2024},
volume = {42},
language = {en},
url = {http://geodesic.mathdoc.fr/item/TAC_2024_42_a6/}
}
TY - JOUR AU - Robin Cockett AU - G.S.H. Cruttwell AU - Jonathan Gallagher AU - Dorette Pronk TI - Factorization Systems for Restriction Categories JO - Theory and applications of categories PY - 2024 SP - 145 EP - 171 VL - 42 UR - http://geodesic.mathdoc.fr/item/TAC_2024_42_a6/ LA - en ID - TAC_2024_42_a6 ER -
Robin Cockett; G.S.H. Cruttwell; Jonathan Gallagher; Dorette Pronk. Factorization Systems for Restriction Categories. Theory and applications of categories, Hofstra Festschrift, Tome 42 (2024), pp. 145-171. http://geodesic.mathdoc.fr/item/TAC_2024_42_a6/