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: Robert is not climbing a mountain. Patricia is cooking if and only if Jennifer is playing tennis. If Robert climbs a mountain, then Jennifer is playing tennis. If Jennifer plays tennis, then Robert is climbing a mountain.
Jennifer is not playing tennis can be inferred via the modus tollens rule. Robert is climbing a mountain if and only if Jennifer is playing tennis can be inferred via the biconditional introduction rule. Jennifer is playing tennis if and only if Robert is climbing a mountain can be inferred via the biconditional introduction rule. If Patricia cooks, then Jennifer is playing tennis can be inferred via the biconditional elimination rule. If Jennifer plays tennis, then Patricia is cooking can be inferred via the biconditional elimination rule.