Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-24T23:32:58.567Z Has data issue: false hasContentIssue false

Connected limits, familial representability and Artin glueing

Published online by Cambridge University Press:  04 March 2009

Aurelio Carboni
Affiliation:
Dipartimento di Matematica, Università di Genova, Italy.
Peter Johnstone
Affiliation:
Department of Pure Mathematics, University of Cambridge, England.

Abstract

We consider the following two properties of a functor F from a presheaf topos to the category of sets: (a) F preserves connected limits, and (b) the Artin glueing of F is again a presheaf topos. We show that these two properties are in fact equivalent. In the process, we develop a general technique for associating categorical properties of a category obtained by Artin glueing with preservation properties of the functor along which the glueing takes place. We also give a syntactic characterization of those monads on Set whose functor parts have the above properties, and whose units and multiplications are cartesian natural transformations.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Artin, M., Grothendieck, A. and Verdier, J. L. (1972) Théorie des Topos (SGA 4, tome I). Springer-Verlag Lecture Notes in Mathematics 269.Google Scholar
Bénabou, J. (1991) Some remarks on free monoids in a topos. In: Category Theory, Springer-Verlag Lecture Notes in Mathematics 1488 2029.CrossRefGoogle Scholar
Carboni, A., Kelly, G. M. and Wood, R. J. (1991) A 2-categorical approach to change of base and geometric morphisms I. Cahiers Top. Géom Diff. 32 4795.Google Scholar
Day, B. (1972) A reflection theorem for closed categories. J. Pure Appl. Alg. 2 111.CrossRefGoogle Scholar
Diers, Y. (1977) Catègories Localisables, Thèse de Doctorat d'Etat, Université de Paris VI.Google Scholar
Diers, Y. (1979) Families universelles de morphismes. Ann. Soc. Sci. Bruxelles 93 175195.Google Scholar
Dyckhoff, R. and Tholen, W. (1987) Exponentiable morphisms, partial products and pullback complements. J. Pure Appl. Alg. 49 103116.CrossRefGoogle Scholar
Freyd, P. J. and Scedrov, A. (1990) Categories, Allegories, North-Holland Mathematical Library vol. 39. North-Holland.Google Scholar
Johnson, M. and Walters, R. F. C. (1992) Algebra objects and algebra families for finite limit theories. J. Pure Appl. Alg. 83 283293.CrossRefGoogle Scholar
Johnstone, P.T. (1977) Topos Theory, L.M.S. Mathematical Monographs 10, Academic Press.Google Scholar
Johnstone, P.T. (1979) Automorphisms of Ω. Algebra Universalis 9 17.CrossRefGoogle Scholar
Johnstone, P.T. (1979a) A syntactic approach to Diers' localizable categories. In: Applications of Sheaves, Springer-Verlag Lecture Notes in Mathematics 753 466478.CrossRefGoogle Scholar
Johnstone, P.T. (1990) Collapsed toposes and cartesian closed varieties. J. Algebra 129 446480.CrossRefGoogle Scholar
Johnstone, P.T. (1992) Partial products, bagdomains and hyperlocal toposes. In: Applications of Categories in Computer Science, L.M.S. Lecture Notes Series 177, Cambridge University Press 315339.CrossRefGoogle Scholar
Jónsson, B. and Nelson, E. (1974) Relatively free products in regular varieties. Algebra Universalis 4 1419.CrossRefGoogle Scholar
Kasangian, S. and Labella, A. (1992) Enriched categorical semantics for distributed calculi. J. Pure Appl. Alg. 83 295321.CrossRefGoogle Scholar
Kasangian, S. and Vigna, S. (1991) Trees in distributive categories. In: Category Theory, Springer-Verlag Lecture Notes in Mathematics 1488 237248.CrossRefGoogle Scholar
Kasangian, S. and Vigna, S. (1991a) Introducing a calculus of trees. In: TAPSOFT '91, vol. 1, Springer-Verlag Lecture Notes in Computer Science 493 215240.CrossRefGoogle Scholar
Kelly, G. M. (1992) On clubs and data-type constructors. In:Applications of Categories in Computer Science, L.M.S. Lecture Notes Series 177, Cambridge University Press 163190.CrossRefGoogle Scholar
Kock, A. (1991) Algebras for the partial map classifier monad. In: Category Theory, Springer-Verlag Lecture Notes in Mathematics 1488 262278.CrossRefGoogle Scholar
Lawvere, F. W. (1973) Metric spaces, generalized logic, and closed categories. Rend. Sem. Mat. Fis. Milano 43 135166.CrossRefGoogle Scholar
Mac Lane, S. (1971) Categories for the Working Mathematician, Graduate Texts in Mathematics 5, Springer-Verlag.CrossRefGoogle Scholar
Paré, R. (1990) Simply connected limits. Canad. J. Math. 42 731746.CrossRefGoogle Scholar
Pasynkov, B. A. (1965) Partial topological products. Trans. Moscow Math. Soc. 13 153272.Google Scholar
Rosebrugh, R.D. and Wood, R. J. (1991) Pullback preserving functors. J. Pure Appl. Alg. 73 7390.CrossRefGoogle Scholar
Street, R. (1976) Limits indexed by category-valued 2-functors. J. Pure Appl. Alg. 8 149181.CrossRefGoogle Scholar
Walters, R.F.C. (1989) Datatypes in distributive categories. Bull. Austral. Math. Soc. 40 7982.CrossRefGoogle Scholar
Walters, R.F.C. (1989a) A note on context-free languages. J. Pure Appl. Alg. 62 199203.CrossRefGoogle Scholar
Walters, R. F. C. (1989b) The free category with products on a multigraph. J. Pure Appl. Alg. 62 205210.CrossRefGoogle Scholar
Walters, R.F.C. (1992) Categories and Computer Science, Cambridge University Press.CrossRefGoogle Scholar
Wraith, G.C. (1974) Artin glueing. J. Pure Appl. Alg. 4 345348.CrossRefGoogle Scholar
Wyler, O. (1991) Lecture Notes on Topoi and Quasitopoi, World Scientific.CrossRefGoogle Scholar