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: It is snowing if and only if Jessica is playing squash. If Susan were a taxi driver, then Jessica is playing squash. It is snowing.
If it snows, then Jessica is playing squash can be inferred via the biconditional elimination rule. If Jessica plays squash, then it is snowing can be inferred via the biconditional elimination rule.