A
bstract_
S
ubstitution
Monoid_Action
Substitution
Substitution_First_Order_Term
Substitution_HOL_ex_Unification
Functional_Substitution
Functional_Substitution_Example
Natural_Magma
Natural_Functor
Natural_Magma_Functor
Functional_Substitution_Lifting
Functional_Substitution_Lifting_Example