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 windy, then Barbara is sleeping. David is cooking if and only if it is snowing. If David cooks, then it is windy. For all y, if y sleeps, then y is working.
If David cooks, then Barbara is sleeping can be inferred via the transitivity rule. If David cooks, then it is snowing can be inferred via the biconditional elimination rule. If it snows, then David is cooking can be inferred via the biconditional elimination rule.