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 if and only if William is running. Charles is playing tennis if and only if William is running. It is sunny. Charles is not playing tennis.
It is sunny and Charles is not playing tennis can be inferred via the conjunction rule. Charles is not playing tennis and it is sunny can be inferred via the conjunction rule. If it snows, then William is running can be inferred via the biconditional elimination rule. If Charles plays tennis, then William is running can be inferred via the biconditional elimination rule. If William goes running, then it is snowing can be inferred via the biconditional elimination rule. If William goes running, then Charles is playing tennis can be inferred via the biconditional elimination rule. William is not running can be inferred via the biconditional elimination rule.