# Tag Info

We can remove the dependence on what the values stored in the sequences are by assuming that we pass "the same thing" as the first two arguments. Regardless of what $b_1, b_2, b_3$ are: $$([b_1b_2b_3]\,x)\,x = \lambda f. ((f\,x)\,x)\,x$$ This gives you an effective way to tell the difference between an empty sequence and a non-empty sequence : (([]\left&...