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: Richard is a poet. If Barbara were fast, then Richard is not a poet. If Joseph were a soldier, then Linda is rich. Joseph is a soldier.
Linda is rich can be inferred via the modus ponens rule. Barbara is not fast can be inferred via the modus tollens rule. Richard is a poet and Joseph is a soldier can be inferred via the conjunction rule. Joseph is a soldier and Richard is a poet can be inferred via the conjunction rule.