Unify = Unifier + WF1 + "NNF" +
datatype 'a subst = Fail | Subst ('a list)
consts
"##" :: "('a => 'b) => ('a => 'c) => 'a => ('b * 'c)" (infixr 50)
R0 :: "('a set * 'a set) set"
R1 :: "(('a uterm * 'a uterm) * ('a uterm * 'a uterm)) set"
R :: "(('a uterm * 'a uterm) * ('a uterm * 'a uterm)) set"
rules
point_to_prod_def "(f ## g) x == (f x, g x)"
(* finite proper subset -- should go in WF1.thy maybe *)
R0_def "R0 == {p. fst p < snd p & finite(snd p)}"
R1_def "R1 == rprod (measure uterm_size) (measure uterm_size)"
(* The termination relation for the Unify function *)
R_def "R == inv_image (R0 ** R1)
((%(x,y). vars_of x Un vars_of y) ## (%x.x))"
end