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 will drive a car or x_13 is not happy. For all x_13, if x_13 reads a book, then x_13 is running. For all x_13, x_13 will go running if and only if x_13 is happy.
There is at least one x_13 for which if x_13 were happy, then x_13 is driving a car can be inferred via the existential rewriting rule. For all x_13, if x_13 goes running, then x_13 is happy can be inferred via the universal biconditional elimination rule. For all x_13, if x_13 were happy, then x_13 is running can be inferred via the universal biconditional elimination rule.