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: For all x, if x works, then x is an artist. For all x, x will not play tennis. For all x, if x were an artist, then x is working. There is at least one x for which x is an artist if and only if x will play tennis.
For all x, x will work if and only if x is an artist can be inferred via the universal biconditional introduction rule. For all x, x is an artist if and only if x will work can be inferred via the universal biconditional introduction rule. There is at least one x for which if x were an artist, then x is playing tennis can be inferred via the existential biconditional elimination rule. There is at least one x for which if x plays tennis, then x is an artist can be inferred via the existential biconditional elimination rule. There is at least one x for which x is not an artist can be inferred via the existential biconditional elimination rule.