enrich
olist
with
functions
sort : List[Tord] → List[Tord];
variables
x : List[Tord];
y : List[Tord];
z : List[Tord];
a : Tord;
b : Tord;
c : Tord;
axioms
Ordered: ordered≤(sort(x));
Perm: perm(x, sort(x));
end enrich