How will we convert an FDD to ZDD?

Question

I saw a previous answered question but got confused with this solution in exam of August 29, 2023, Problem 1.e.
I understood the general working of converting an FDD to ZDD. One solution being to able to convert it via truth table which will be too long for 4 variables. And the other solution being

1. get the set representation of the FDD
2. determine the RMF of the set representation
3. convert the RMF to DNF (expand the cubes of the DNF to midterms)
4. convert the DNF to a set representation of the ZDD
5. write down the ZDD from the set representation of step 4

How is this solved?

Thank you.

Answer 1

There are many ways how you can convert one canonical normal form A to another canonical normal form B, in particular, using other normal forms C,D,... in between. In the lecture slides, you can find functions FDD2BDD and BDD2ZDD that you can also use. However, the best way is typically the one used in the solution that you precisely described with the 5 steps in your question. Which one of the five steps troubles you?