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: For all y, y is a soldier or y is not an office clerk. For all y, y is an office clerk or y is a lawyer. For all y, y is a soldier if and only if y is a lawyer.
For all y, if y were an office clerk, then y is a soldier can be inferred via the universal rewriting rule. For all y, if y were a soldier, then y is a lawyer can be inferred via the universal biconditional elimination rule. For all y, if y were a lawyer, then y is a soldier can be inferred via the universal biconditional elimination rule.