comp-atom-ap(g;f;x;a)
== let f' = a.g o f in
== let x' = a.x in
== let F = b,c. f'(b,x'(c)) in
== let L = atoms-in(F) in
== let b = new-atom((a.L)) in
== if F(b,a)=aAtom inr(f'(b))
== i; F(a,b)=aAtom inl(f.g(f(x'(b))))
== else inr(x.hd(list-diff(AtomDeq;monitor((f'(b,x)));b.L))) fi