Make.Cval are_convertible : convertibility_testare_convertible sg t1 t2 checks whether t1 and t2 are convertible or not in the signature sg.
val constraint_convertibility :
Rule.constr ->
Rule.rule_name ->
convertibility_testconstraint_convertibility cstr r sg [t1] [t2] checks wehther the [cstr] of the rule [r] is satisfiable. Because constraints are checked once a term has matched the pattern, satisfying a constraint comes back to check that two terms are convertible