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: If William were an office clerk, then it is overcast. It is not overcast. If Michael were not an artist, then John is playing tennis. William is an office clerk if and only if Michael is an artist.
William is not an office clerk can be inferred via the modus tollens rule. If William were an office clerk, then Michael is an artist can be inferred via the biconditional elimination rule. If Michael were an artist, then William is an office clerk can be inferred via the biconditional elimination rule.