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: Linda is a sailor if and only if Karen is a writer. If Michael were a cashier, then Karen is a writer. Linda is not a sailor. If Karen were a writer, then Michael is a cashier.
Michael is a cashier if and only if Karen is a writer can be inferred via the biconditional introduction rule. Karen is a writer if and only if Michael is a cashier can be inferred via the biconditional introduction rule. If Linda were a sailor, then Karen is a writer can be inferred via the biconditional elimination rule. If Karen were a writer, then Linda is a sailor can be inferred via the biconditional elimination rule. Karen is not a writer can be inferred via the biconditional elimination rule.