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 overcast if and only if Jennifer is drinking water. It is not overcast. Jennifer is drinking water or Robert is taking a plane.
If it is overcast, then Jennifer is drinking water can be inferred via the biconditional elimination rule. If Jennifer drinks water, then it is overcast can be inferred via the biconditional elimination rule. Jennifer is not drinking water can be inferred via the biconditional elimination rule.