### Assignment 3, Task 2 and Task 4

Verfasst:

**6. Mai 2014 18:37**Hey there,

I got some questions:

In the task description we are asked to implement a function which computes a sublist.

In the fourth task we have to implement a fold function on a binary tree. It is not specified how a fold function would work on binary trees and I was not able to find any hints on the internet. Could you please specify this function or refer to an adequate source?

Thanks in advance!

I got some questions:

**Question regarding task 2:**In the task description we are asked to implement a function which computes a sublist.

I don't exactly get how these sublists are supposed to be assembled. The description doesn't answer some questions. It says "[...] ys is the result of remove some (or no) elements from xs." This doesn't specify if all permutations have to be in the list, or just one we can randomly pick.Implement the function sublists which takes a list xs and computes the set X of all lists such that for all ys in X, ys is the result of removing some (or no) elements from xs. Implement sublists with some flavor of fold.

**Question regarding task 4:**In the fourth task we have to implement a fold function on a binary tree. It is not specified how a fold function would work on binary trees and I was not able to find any hints on the internet. Could you please specify this function or refer to an adequate source?

Thanks in advance!