Hi,
I need to write a pesudocode about InvertRelation function for 2-level Binary Decision diagrams.
InvertRelation takes as input a 2L-level quasi-reduced BDD rooted at r encoding a relation R : BL → 2{BL} and returns the 2L-level quasi-reduced BDD rooted at s encoding the relation R{−1} :BL →2{BL},that is, j ∈ R(i) iff i ∈ R{−1}(j).
the input BDD r uses the variable order x′1, x1, ..., x′L, xL and that the result BDD s uses the variable order x1,x′1,...,xL,x′L. Thus r is at level L and its children are at level L′, while s is at level L′ and its children are at level L.

Any help is appreciated.