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: John is climbing a mountain if and only if Joseph is drinking water. For all x_10, x_10 will not drink water.
If John climbs a mountain, then Joseph is drinking water can be inferred via the biconditional elimination rule. If Joseph drinks water, then John is climbing a mountain can be inferred via the biconditional elimination rule.