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 windy. David is taking a plane if and only if it is late. It is late if and only if Jessica is climbing a mountain. David is not taking a plane.
It is windy and David is not taking a plane can be inferred via the conjunction rule. David is not taking a plane and it is windy can be inferred via the conjunction rule. If David takes a plane, then it is late can be inferred via the biconditional elimination rule. If it is late, then Jessica is climbing a mountain can be inferred via the biconditional elimination rule. If it is late, then David is taking a plane can be inferred via the biconditional elimination rule. If Jessica climbs a mountain, then it is late can be inferred via the biconditional elimination rule. It is not late can be inferred via the biconditional elimination rule.