Abstract
We give a new version of Galois theory in categories in which normal extensions are replaced by arbitrary extensions for which the “pullback functor” is monadic, and their Galois groupoids are replaced by internal pregroupoids; we obtain the “fundamental theorem of Galois theory” using just simple remarks on internal precategories and change of universe for internal functors.
I would like to thank Aurelio Carboni at Milan University for inviting me for extended visit in Summer 1990 during which the work on this paper was completed.
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References
M. Bunge, Open covers and the fundamental localic groupoid of a topos, McGill Univ. Math. Preprint 89–33 (1989).
A. Grothendieck, Revêtements étales et groupe fondamental, SGA 1, Springer Lecture Notes in Math. 269 (1972).
G. Janelidze, Galois extensions of commutative rings by profinite families of groups, Transactions of Razmadze Math. Inst. of the Georgian Acad. Sci. 74 (1983), 39–51 (in Russian).
G. Janelidze, Magid theorem in categories, Bull. Georgian Acad. Sci. 114(3) (1984), 497–500 (in Russian).
G. Janelidze, A generalization of the theory of covering spaces, IV International Conf. in Topology and its Applications, Abstract of Reports, Dubrovnic (1985).
G. Janelidze, (G.Z. Dzhanelidze), The fundamental theorem of Galois theory, Math. USSR Sbornik 64(2) (1989), 359–374.
G. Janelidze, Pure Galois theory in categories, U.C.N.W. Pure Math. Preprint 87.20 (Bangor 1987) (and to appear in Journal of Algebra).
G. Janelidze, Galois theory in categories: the new example of differential fields, Categorical Topology (Proc. Conf. in Prague), World Scientific (1988), 369–380.
G. Janelidze, What is a double central extension — the question was given by Ronnie Brown, to appear.
G. Janelidze, A note on Barr-Diaconescu covering theory, to appear.
G. Janelidze, Change of universe in the category of internal functors, McGill Univ. Math. Preprint 90–11 (1990).
J. Kennison, What is the fundamental group?, J. Pure Appl. Algebra 59 (1989), 187–200.
A.R. Magid, The separable Galois theory of commutative rings, Marsel Dekker (1974).
R.S. Pierce, Modules over commutative regular rings, Mem. AMS 70 (1967).
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© 1991 Springer-Verlag
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Janelidze, G. (1991). Precategories and Galois theory. In: Carboni, A., Pedicchio, M.C., Rosolini, G. (eds) Category Theory. Lecture Notes in Mathematics, vol 1488. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0084218
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DOI: https://doi.org/10.1007/BFb0084218
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