John Carlos Baez

Excellent article and great pictures!

Here's my short introduction to spinors which explains the difference between Dirac spinors, Weyl spinors, Majorana spinors and Majorana-Weyl spinors. Trautman's book The Spinorial Chessboard is dense but packed with good info:

I recommend first Tom Leinster's textbook and then Emily Riehl's textbook on category theory - or maybe both simultaneously. They're both free! Check out the very bottom of my book recommendation page:

I recommend first Tom Leinster's textbook and then Emily Riehl's textbook on category theory - or maybe both simultaneously. They're both free! Check out the very bottom of my book recommendation page:

I just re-read it. It's great, in part because it reveals things about Thurston as a human being.