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: Elisabeth is not playing tennis. If Thomas were an artist, then Elisabeth is playing tennis. If Elisabeth plays tennis, then Thomas is an artist. If it is cloudy, then Thomas is an artist.
Thomas is not an artist can be inferred via the modus tollens rule. Thomas is an artist if and only if Elisabeth is playing tennis can be inferred via the biconditional introduction rule. Elisabeth is playing tennis if and only if Thomas is an artist can be inferred via the biconditional introduction rule.