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: David is a carpenter if and only if Michael is happy. David is a carpenter or it is not cold.
If it is cold, then David is a carpenter can be inferred via the rewriting rule. If David were a carpenter, then Michael is happy can be inferred via the biconditional elimination rule. If Michael were happy, then David is a carpenter can be inferred via the biconditional elimination rule.