Tidy up ObjC memoization notes.
Abbreviate Swift memoization code.
Swift memoization notes.
Nullability notes.
ObjC nullability & pattern matching notes.
Remove the lead-in.
Swift nullability notes.
Lead in to nontermination & fixpoints.
Nontermination in nullability.
MATH
Suspense!
Fixpoint notes.
ObjC fixpoint notes.
Swift fixpoint notes.
Move that lead-in.
Parse forest notes.