construction of ZDD and ROBDD

Question

I am comfused in constructing ROBDD and ZDD for given any propostional equation?

for both we need to convert equation to snf and draw diagram

then what is difference between ROBDD and ZDD for given any propostional equation?

Answer 1

ZDD and BDDs use both the Shannon expansion as you say. However, they use different elimination rules. While BDDs eliminate nodes like (a=>b|b), ZDDs eliminate nodes (a=>0|b) which is also the same elimination rule as used by FDDs. See slide 138 of the related chapter.