It is well known that the category of covering projections (that is, locally constant objects) of a locally connected topos is equivalent to the classifying topos of a strict progroupoid (or, equivalently, a localic prodiscrete groupoid), the fundamental progroupoid, and that this progroupoid represents first degree cohomology. In this paper we generalize these results to an arbitrary topos. Th...

We give a constructive localic account of the completion of quasimetric spaces. In the context of Lawvere’s approach, using enriched categories, the points of the completion are flat left modules over the quasimetric space. The completion is a triquotient surjective image of a space of Cauchy sequences and can also be embedded in a continuous dcpo, the “ball domain”. Various examples and constr...

The notion of a (pointed) Galois pretopos (“catégorie galoisienne”) was considered originally by Grothendieck in [12] in connection with the fundamental group of an scheme. In that paper Galois theory is conceived as the axiomatic characterization of the classifying pretopos of a profinite group G. The fundamental theorem takes the form of a representation theorem for Galois pretopos (see [10] ...

1 Generalities on Spectral Deligne-Mumford Stacks 4 1.1 Points of Spectral Deligne-Mumford Stacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Étale Morphisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 Localic Spectral Deligne-Mumford Stacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.4 Quasi-Compactness of Sp...

The familiar classical result that a continuous map from a space $X$ to a space $Y$ can be defined by giving continuous maps $varphi_U: U to Y$ on each member $U$ of an open cover ${mathfrak C}$ of $X$ such that $varphi_Umid U cap V = varphi_V mid U cap V$ for all $U,V in {mathfrak C}$ was recently shown to have an exact analogue in pointfree topology, and the same was done for the familiar cla...