Grothendieck topos
= Grothendieck topos
{c}
A Grothendieck topos is a category equivalent to the <sheaves on a site> for a small <Grothendieck topology>. It is an <elementary topos> with all small colimits and a small generating family. Small disjoint coproducts, effective quotients and the set of subobjects of any fixed object allow many constructions by unions.