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_15, x_15 will take a plane or x_15 is a bartender. There is at least one x_15 for which x_15 is an artist if and only if x_15 will climb a mountain. For all x_15, x_15 is an artist if and only if x_15 will take a plane. For all x_15, x_15 will not climb a mountain.
For all x_15, if x_15 were an artist, then x_15 is taking a plane can be inferred via the universal biconditional elimination rule. There is at least one x_15 for which if x_15 were an artist, then x_15 is climbing a mountain can be inferred via the existential biconditional elimination rule. For all x_15, if x_15 takes a plane, then x_15 is an artist can be inferred via the universal biconditional elimination rule. There is at least one x_15 for which if x_15 climbs a mountain, then x_15 is an artist can be inferred via the existential biconditional elimination rule. There is at least one x_15 for which x_15 is not an artist can be inferred via the existential biconditional elimination rule.