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, x is a mechanic or x will not play tennis. There is at least one x for which x will play tennis or x is not a writer.
For all x, if x plays tennis, then x is a mechanic can be inferred via the universal rewriting rule. There is at least one x for which if x were a writer, then x is playing tennis can be inferred via the existential rewriting rule.