Calc
FreshVar()
FreshVars()
Inductive()
Lemma
NewType()
Proof
QExists()
QForAll()
Struct()
axiom()
cond()
define()
prove()
search()
simp()
AddSemigroup
CommAddSemigroup
CommSemigroup
Group
Monoid
SemiGroup
check_semigroup()
S (SemiGroup)