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 fast or it is late. David is not fast. If Jennifer were a politician, then it is late. If it is late, then Jennifer is a politician.
It is late can be inferred via the disjunctive syllogism rule. Jennifer is a politician if and only if it is late can be inferred via the biconditional introduction rule. It is late if and only if Jennifer is a politician can be inferred via the biconditional introduction rule.