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 Charles were bored, then Richard is a mechanic. Richard is a mechanic. If Richard were a mechanic, then Charles is bored.
Charles is bored can be inferred via the modus ponens rule. Charles is bored if and only if Richard is a mechanic can be inferred via the biconditional introduction rule. Richard is a mechanic if and only if Charles is bored can be inferred via the biconditional introduction rule.