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 Mary were a doctor, then Robert is climbing a mountain. Mary is a doctor or Patricia is not a janitor. If Robert climbs a mountain, then Mary is a doctor. Robert is climbing a mountain or Patricia is a janitor.
If Patricia were a janitor, then Mary is a doctor can be inferred via the rewriting rule. Mary is a doctor if and only if Robert is climbing a mountain can be inferred via the biconditional introduction rule. Robert is climbing a mountain if and only if Mary is a doctor can be inferred via the biconditional introduction rule.