Calc
Inductive()
Lemma
NewType()
Proof
QExists()
QForAll()
Struct()
axiom()
cond()
define()
prove()
search()
simp()
skolem()
Defn
LemmaError
andI()
beta_conv()
cong()
consider()
define_fix()
defns
einstan()
eqrefl()
eqsym()
eqtrans()
forget()
forget2()
fresh_const()
herb()
induct_inductive()
instan()
instan2()
is_defined()
is_proof()
modus()
proj()
subst()
Skolemize an existential quantifier.
pf (Proof)
tuple[list[ExprRef], Proof]