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_5, if x_5 plays squash, then x_5 is an artist. For all x_5, if x_5 were a sailor, then x_5 is playing squash. For all x_5, if x_5 were an artist, then x_5 is playing squash.
For all x_5, if x_5 were a sailor, then x_5 is an artist can be inferred via the universal transitivity rule. For all x_5, x_5 will play squash if and only if x_5 is an artist can be inferred via the universal biconditional introduction rule. For all x_5, x_5 is an artist if and only if x_5 will play squash can be inferred via the universal biconditional introduction rule.