Calc
FreshVar()
FreshVars()
Inductive()
Lemma()
NewType()
PTheorem()
Proof
QExists()
QForAll()
QImplies()
Struct()
Theorem()
axiom()
cond()
define()
prove()
search()
simp()
MImplies()
Box()
PEq()
PIf()
PImplies()
PointEq()
PointIf()
Valid()
coerce()
https://en.wikipedia.org/wiki/Modal_companion