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: David is fast or Elisabeth is not playing a game. If David were fast, then William is a mechanic. If William were a mechanic, then Elisabeth is playing a game.
If David were fast, then Elisabeth is playing a game can be inferred via the transitivity rule. If Elisabeth plays a game, then David is fast can be inferred via the rewriting rule.