![[1242] Réfutation de la conjecture du télescope de Ravenel](/media/cache/video_light/uploads/video/SeminaireBourbaki.jpg)
published on December 9, 2025
[1242] Réfutation de la conjecture du télescope de Ravenel
By Christian Ausoni
3/4 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.
