Consider the following premises. u <-> p. forall x: ~T(x). forall x: T(x) or R(x). ~u. Can we infer p from them? If possible, name the inference rules being used at each step.
 From forall x: T(x) or R(x), forall x: ~T(x) we can infer forall x: R(x) via universal disjunctive syllogism. Finally, from u <-> p, ~u we can infer ~p via biconditional elimination, which contradicts p. Therefore, the answer is no.