published on February 23, 2026
Illustration in Mathematics and CS — Made Broadly Accessible by AI: From Opportunity to Practice
By Erika Berenice Roldan Roa
1/4 A crash course in topos theory : the big picture
By André Joyal
Appears in collection : Topos à l'IHES
About half of the topos theory of SGA4 is devoted to categorical generalities. They are now subsumed by the modern theory of (locally) presentable categories. I will sketch this theory, stressing the results that are important for topos theory. The category of complete lattices and sup-preserving maps is a toy example of this theory.
