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 Barbara were curious, then Sarah is climbing a mountain. If Richard plays squash, then Karen is a server. Sarah is climbing a mountain if and only if Richard is playing squash.
If Sarah climbs a mountain, then Richard is playing squash can be inferred via the biconditional elimination rule. If Richard plays squash, then Sarah is climbing a mountain can be inferred via the biconditional elimination rule.