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: John is a police officer if and only if it is overcast. It is not overcast. Linda is listening to a song.
It is not overcast and Linda is listening to a song can be inferred via the conjunction rule. Linda is listening to a song and it is not overcast can be inferred via the conjunction rule. If John were a police officer, then it is overcast can be inferred via the biconditional elimination rule. If it is overcast, then John is a police officer can be inferred via the biconditional elimination rule. John is not a police officer can be inferred via the biconditional elimination rule.