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 server. There is at least one y for which y will write a letter or y will not play a game. For all y, if y were a server, then y is playing a game.
For all y, y will play a game can be inferred via the universal modus ponens rule. There is at least one y for which if y plays a game, then y is writing a letter can be inferred via the existential rewriting rule.