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 rains, then it is overcast. It is late if and only if Mary is an electrician. Mary is an electrician or it is raining. It is not late.
If it is late, then Mary is an electrician can be inferred via the biconditional elimination rule. If Mary were an electrician, then it is late can be inferred via the biconditional elimination rule. Mary is not an electrician can be inferred via the biconditional elimination rule.