Oh, neat! I knew that topoi were an alternative mathematical foundation, but this is the first time I've seen it explained in a way that I could understand. I'v

Oh, neat! I knew that topoi were an alternative mathematical foundation, but this is the first time I've seen it explained in a way that I could understand. I've tried attacking the explanations on Wikipedia but my head just started spinning around each time I did it. I made it to page 8 here before I got a bit bogged down and would need to take a pad of paper out to keep following. I do enjoy this dense yet accessible style of mathematics text, it reminds my of the notes I would get from the most seasoned professors in the mathematics department... you know, the ones that have been around forever and care about teaching.