> a tree that may have no bottom If we're allowing unbounded (co)datastructures then a singly-linked list will do the trick. Perhaps these examples don't coun

> a tree that may have no bottom If we're allowing unbounded (co)datastructures then a singly-linked list will do the trick. Perhaps these examples don't count since they're not computable functions. Specifically, searching for an element in a bottomless tree/list that doesn't contain it will not halt, making this a partial function.