What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: u <-> s_3. ~u. p -> t. s_3 or p.
u -> s_3 can be inferred via the biconditional elimination rule. s_3 -> u can be inferred via the biconditional elimination rule. ~s_3 can be inferred via the biconditional elimination rule.