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_13 for which x_13 is bored or x_13 will play squash. For all x_13, x_13 will drive a car. For all x_13, if x_13 were bored, then x_13 is working. For all x_13, x_13 will work if and only if x_13 will play squash.
For all x_13, if x_13 works, then x_13 is playing squash can be inferred via the universal biconditional elimination rule. For all x_13, if x_13 plays squash, then x_13 is working can be inferred via the universal biconditional elimination rule.