I recently learnt about the concept of dominator trees and was fascinated by it.
I was wondering how the problem extends to computing dominators from multiple sources, or even from all vertices in the graph as sources: can all-sources dominators be represented more compactly than in O(n^2) space and computed more efficiently than running the classic dominator tree algorithm from every vertex?
I tried searching for keywords like "multiple sources dominators" etc, but only found about "multiple-vertex dominators", which are a different thing (dominating sets of size > 1)
Does any of this become simpler if the graph is acyclic? (in fact, I work at Google and I think it'd be fun to apply this to the huge dependency graph of Google's build targets)