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 Jennifer were an artist, then it is not cold. It is cold. For all x_17, if x_17 were an artist, then x_17 is a nurse. For all x_17, if x_17 were a nurse, then x_17 is an artist.
Jennifer is not an artist can be inferred via the modus tollens rule. For all x_17, x_17 is an artist if and only if x_17 is a nurse can be inferred via the universal biconditional introduction rule. For all x_17, x_17 is a nurse if and only if x_17 is an artist can be inferred via the universal biconditional introduction rule.