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, y is a bartender or y will not write a letter. There is at least one y for which y will write a letter or y is not a bartender.
For all y, if y writes a letter, then y is a bartender can be inferred via the universal rewriting rule. There is at least one y for which if y were a bartender, then y is writing a letter can be inferred via the existential rewriting rule.