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 not late. It is overcast if and only if it is late. If it is overcast, then it is late.
It is not overcast can be inferred via the modus tollens rule. If it is overcast, then it is late can be inferred via the biconditional elimination rule. If it is late, then it is overcast can be inferred via the biconditional elimination rule. It is not overcast can be inferred via the biconditional elimination rule.