The least subtopos containing the discrete skeleton of Ω

Abstract

Let p : E → S be a pre-cohesive geometric morphism. We show that theleast subtopos of E containing both the subcategories p∗ : S → E and p! : S → E ex-ists, and that it coincides with the least subtopos containing p∗2 , where 2 denotes thesubobject classifier of S.