### Differential Geometry

So today I read up on this titular subject, and came to the conclusion that it is the possibly cannibis-induced lovechild of set theory and vector calculus. For those unfamiliar with the subjects, they are two very core fields in mathematics. I know many people who are good at one and only one (myself included); I know of none adept at both.

The following words have defined mathematical meanings that I was completely unaware of before today:

- Patch
- Umbilical
- Monkey saddle
- Maximal
- Compact
- Pullback
- Pushout
- Categorical dual
- Bundle
- Fibre product
- Functor

Update: I reworded things a little, as previously this entry sounded far more harshly than I intended.