What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_13, if x_13 plays a game, then x_13 is a sailor. David is a sailor or Elisabeth is not running. For all x_13, if x_13 were a sailor, then x_13 is playing a game.
If Elisabeth goes running, then David is a sailor. For all x_13, x_13 will play a game if and only if x_13 is a sailor. For all x_13, x_13 is a sailor if and only if x_13 will play a game.