A book cover a day. #25

[juan_gandhi]

Mac Lane, Moerdijk.

Seems like every time I bump into a problem and spend a week googling and trying to figure out, I should just open this book and find an explicit answer. In other publications they just say "it can be easily proved that..."

E.g. try to prove that in a well-pointed topos Ω≅1+1

Comments

[dmm]

A great book.

I've attended an invited talk by the second author 4 years ago:

https://sites.google.com/site/summertopology/home