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 z for which z will not go running. For all z, z will work or z will write a letter. For all z, z will play squash if and only if z will work. For all z, z will play squash if and only if z will go running.
For all z, if z plays squash, then z is working can be inferred via the universal biconditional elimination rule. For all z, if z plays squash, then z is running can be inferred via the universal biconditional elimination rule. For all z, if z works, then z is playing squash can be inferred via the universal biconditional elimination rule. For all z, if z goes running, then z is playing squash can be inferred via the universal biconditional elimination rule. There is at least one z for which z will not play squash can be inferred via the existential biconditional elimination rule.