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 is cold, then Mary is working. Mary is working if and only if it is cold. If it is cold, then Mary is working.
If Mary works, then it is cold can be inferred via the biconditional elimination rule. If it is cold, then Mary is working can be inferred via the biconditional elimination rule.