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 late if and only if Sarah is a politician. It is not late. James is excited and Thomas is fast.
James is excited can be inferred via the simplification rule. Thomas is fast can be inferred via the simplification rule. If it is late, then Sarah is a politician can be inferred via the biconditional elimination rule. If Sarah were a politician, then it is late can be inferred via the biconditional elimination rule. Sarah is not a politician can be inferred via the biconditional elimination rule.