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_3. p_15 -> p. p_15 or q. s_1 <-> u_3. q -> p.
p can be inferred via the disjunction elimination rule. s_1 -> u_3 can be inferred via the biconditional elimination rule. u_3 -> s_1 can be inferred via the biconditional elimination rule. ~s_1 can be inferred via the biconditional elimination rule.