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: There is at least one x for which x is poor or x will not play squash. For all x, x is poor if and only if x will play squash.
There is at least one x for which if x plays squash, then x is poor can be inferred via the existential rewriting rule. For all x, if x were poor, then x is playing squash can be inferred via the universal biconditional elimination rule. For all x, if x plays squash, then x is poor can be inferred via the universal biconditional elimination rule.