Doubt in ZDD to FDD Conversion

Question

Question number 1)d) in August 27, 2019 paper.

Convert ZDD to FDD.

I got the following set representation : {a,b,c}, {b}, {a,c}

Then after expansion to RMNF and cancelling out common terms,

I got the following CDNF : a&b&c | a&b&!c | a&!b&c | !a&b&c | !a&b&!c

After decomposition I got the following FDD :

 

But According to the solution, there is an extra outgoing edge from the left c to 0.

What am I missing here?

Also, Is it possible for a node to have more than 2 outgoing edges?

The solution image : 

Answer 1

The extra edge from the left node labeled with c to the 0-leaf should not be there, that was an error in the drawing that has now been fixed. Thanks for pointing this out!

As we have binary decision diagrams, there are always two outgoing edges in the nodes, except that we omit drawing the 0-leaf in which case all missing edges are understood as edges connecting the 0-leaf.

Comments

I got it.. Thank you very much:)!