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: It is windy if and only if Thomas is a politician. Richard is working. Thomas is not a politician.
Richard is working and Thomas is not a politician can be inferred via the conjunction rule. Thomas is not a politician and Richard is working can be inferred via the conjunction rule. If it is windy, then Thomas is a politician can be inferred via the biconditional elimination rule. If Thomas were a politician, then it is windy can be inferred via the biconditional elimination rule. It is not windy can be inferred via the biconditional elimination rule.