sub_one
left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
ret_rl = remove_range(left_orig, min, sub_one(rl_min(right_orig)));