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_6, if x_6 climbs a mountain, then x_6 is bored. For all x_6, x_6 is excited. There is at least one x_6 for which x_6 is bored if and only if x_6 is excited.
There is at least one x_6 for which if x_6 were bored, then x_6 is excited can be inferred via the existential biconditional elimination rule. There is at least one x_6 for which if x_6 were excited, then x_6 is bored can be inferred via the existential biconditional elimination rule.