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: Mary is a carpenter if and only if Sarah is a politician. Sarah is a politician. Barbara is poor.
Sarah is a politician and Barbara is poor can be inferred via the conjunction rule. Barbara is poor and Sarah is a politician can be inferred via the conjunction rule. If Mary were a carpenter, then Sarah is a politician can be inferred via the biconditional elimination rule. If Sarah were a politician, then Mary is a carpenter can be inferred via the biconditional elimination rule.