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