Spahn factorization system (Rev #6)



Let CC be a category. A kk-ary factorization system in CC is defined to be a (ordered) list (L 1,R 1),,(L k1,R k1)(L_1,R_1),\dots,(L_{k-1},R_{k-1}) of (orthogonal) factorization systems such that R iR i+1R_i\supseteq R_{i+1} (or equivalently L i+1L iL_{i+1}\subseteq L_i).

This is equivalent: Every CC-morphism ff factors as f=f 1;f 2;;f kf=f_1;f_2;\dots;f_k with f iR iL i1f_i\in R_i\cap L_{i-1}

Reflective factorization system

reflective factorization system?

Relation of reflective subcategories and reflective subfibrations



Let f:CDf:C\to D be a morphism in a (higher) category 𝒞\mathcal{C}. The nn-image /Postnikov factorization (niP) of ff

f=(Cim (f)im n(f)im n1(f)im 1(f)im 0D)f=(C\simeq im_\infty(f)\to\dots\to im_n (f)\to\im_{n-1}(f)\to\dots\to im_1(f)\to im_0\simeq D)

is defined by (…)

Let \sharp be a (…) monad on 𝒞\mathcal{C}. We consider the niP of the unit η:CC\eta:C\to \sharp C which we denote by

η=(C C nC n1C 0C)\eta=(C\simeq \sharp_\infty C\to \dots\to \sharp_n C\to \sharp_{n-1} C\to\dots\to \sharp_0\simeq \sharp C)


Factorization systems in cohesive toposes

pi-factorization systems


  • Cassidy and Hébert and Kelly?, “Reflective subcategories, localizations, and factorization systems”. J. Austral. Math Soc. (Series A) 38 (1985), 287–329 (pdf)
  • Carboni and Janelidze? and Kelly? and Paré, “On localization and stabilization for factorization systems”, Appl. Categ. Structures 5 (1997), 1–58
  • Mike Shulman, internalizing the external - the joy of codiscreteness, blog

  • J. M. E. Hyland, 27.11.2012, Classical lambda calculus in modern dress, arXiv:1211.5762

  • UF-IAS-2012, Modal type theory, wiki

  • higher modalities, Michael Shulman, pdf

  • Steve Awodey, Nicola Gambino, and Kristina Sojakova. Inductive types in homotopy type theory. To appear in LICS 2012; arXiv:1201.3898, 2012. 1

  • Ching, Bar construction for topological operads (pdf)

Revision on December 2, 2012 at 17:33:00 by Stephan Alexander Spahn?. See the history of this page for a list of all contributions to it.