explain recursion on product types better, fix #311
remove tilde, fix #309
Merge pull request #321 from mikeshulman/products

explain recursion on product types better, fix #311
base is a point in the 1-sphere, not a nat
Merge pull request #322 from jcreedcmu/master

base is a point in the 1-sphere, not a nat
typo
fix sort order in index