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 it rains, then James is playing squash. If James plays squash, then it is raining.
It is raining if and only if James is playing squash can be inferred via the biconditional introduction rule. James is playing squash if and only if it is raining can be inferred via the biconditional introduction rule.