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: It is snowing or Susan is climbing a mountain. It is cloudy if and only if Susan is climbing a mountain. It is not cloudy.
If Susan doesn't climb a mountain, then it is snowing can be inferred via the rewriting rule. If it is cloudy, then Susan is climbing a mountain can be inferred via the biconditional elimination rule. If Susan climbs a mountain, then it is cloudy can be inferred via the biconditional elimination rule. Susan is not climbing a mountain can be inferred via the biconditional elimination rule.