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 late, then Thomas is rich. It is cold. Richard is a musician or it is late. Richard is a musician if and only if Thomas is rich.
If Richard were a musician, then Thomas is rich can be inferred via the biconditional elimination rule. If Thomas were rich, then Richard is a musician can be inferred via the biconditional elimination rule.