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: For all x_5, x_5 is not a carpenter. For all x_5, x_5 will play squash or x_5 will not write a letter. There is at least one x_5 for which if x_5 plays squash, then x_5 is a carpenter.
There is at least one x_5 for which x_5 will not play squash can be inferred via the existential modus tollens rule. For all x_5, if x_5 writes a letter, then x_5 is playing squash can be inferred via the universal rewriting rule.