Axiom
CM6 :
seq (comm (ia E a e) (ia F b f)) x = comm (ia E a e) (seq (ia F b f) x).
Axiom
CM7 :
seq (comm (ia E a e) (ia F b f)) (mer x y) =
comm (seq (ia E a e) x) (seq (ia F b f) y).

(* Specifications: *)
Axiom CM8 : alt (comm x z) (comm y z) = comm (alt x y) z.
Axiom CM9 : alt (comm x y) (comm x z) = comm x (alt y z).
End PARALLEL_OPERATORS.