todo:
-
edit natural-numbers/basics now that we have direct sums
-
edit semigroups/basics now that we have direct sums
-
can we migrate sniffs from nbloomf.md?
-
favicon
-
after times, talk about semigroups again
- define monoid, commutative, cancellative
- prove that End(N,\plus) \cong whatever it is isomorphic to
-
lattices
-
N
-
lists
-
Z