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 x_11, if x_11 plays a game, then x_11 is playing squash. For all x_11, if x_11 climbs a mountain, then x_11 is a writer. There is at least one x_11 for which x_11 is a cashier or x_11 will play a game. For all x_11, x_11 is not a cashier or x_11 will climb a mountain. For all x_11, x_11 will play squash if and only if x_11 is a writer.
There is at least one x_11 for which x_11 will play a game or x_11 will climb a mountain can be inferred via the existential resolution rule. For all x_11, if x_11 plays squash, then x_11 is a writer can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 were a writer, then x_11 is playing squash can be inferred via the universal biconditional elimination rule.