MAYBE Problem: strict: b(p(b(x1))) -> b(q(b(x1))) weak: 1(p(0(1(0(x1))))) -> p(x1) q(x1) -> 0(q(0(x1))) q(x1) -> 1(q(1(x1))) q(x1) -> 0(p(0(x1))) q(x1) -> 1(p(1(x1))) Proof: Open