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: If it is windy, then Robert is running. If Robert goes running, then it is windy. If it is windy, then Richard is not a janitor. Richard is a janitor.
It is not windy can be inferred via the modus tollens rule. If Robert goes running, then Richard is not a janitor can be inferred via the transitivity rule. It is windy if and only if Robert is running can be inferred via the biconditional introduction rule. Robert is running if and only if it is windy can be inferred via the biconditional introduction rule.