Simple function INTERSECTALL efficiently returns intersections of given set of sets, computed combinatorially. It returns cell array of vectors of indices of a set that have instersection to any other set and a vector that gives number of intersections for each set. INTERSECTALLSET is much simpler, it returns the values of the set which are members of all sets.
Thanks for the feedback. I have added one more utility, called INTERSECTALLSET. It does what you need. Also, I've updated the description, hoping that now it is clear what INTERSECTALL produces.
what I expect to find in the intersection of these 3 maps are the indices that are in all sets, i.e.
[3 6 7]. Is it possible to get that with your code?