Consider the following premises. W(e) -> p. u. S(e) -> p. forall y: W(y) or S(y). Can we infer ~p from them?
 From forall y: W(y) or S(y) we can infer W(e) or S(e). Finally, from W(e) -> p, S(e) -> p, W(e) or S(e) we can infer p, which contradicts ~p. Therefore, the answer is no.