What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_11, x_11 is poor if and only if x_11 will climb a mountain. If Thomas writes a letter, then David is running. David is not running. Linda is not climbing a mountain.
Thomas is not writing a letter. David is not running and Linda is not climbing a mountain. Linda is not climbing a mountain and David is not running. For all x_11, if x_11 were poor, then x_11 is climbing a mountain. For all x_11, if x_11 climbs a mountain, then x_11 is poor.