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: If Patricia plays a game, then Elisabeth is happy. Joseph is sleeping or Elisabeth is not happy. Patricia is playing a game or Joseph is not sleeping.
If Elisabeth were happy, then Joseph is sleeping can be inferred via the rewriting rule. If Joseph sleeps, then Patricia is playing a game can be inferred via the rewriting rule.