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 Thomas is an electrician. If Richard were a cashier, then Thomas is an electrician. Richard is not a cashier. Richard is a cashier if and only if Thomas is an electrician.
If Richard were a cashier, then Thomas is an electrician can be inferred via the biconditional elimination rule. If Thomas were an electrician, then Richard is a cashier can be inferred via the biconditional elimination rule. Thomas is not an electrician can be inferred via the biconditional elimination rule.