Hi, the dominator_tree function in graph_tool.topology outputs a vertex property map that codifies a graph. To use the other graph_tool algorithms, it would be beneficial to get the dominator_tree back as Graph (or better GraphView). Is there already a way to do this? Otherwise, how do you like the idea to implement it? A possible use case is it to check, if a dominates b. This would be the pseudo code, if dominator_tree returns a graph like object: dom_tree = graph_tool.topology.dominator_tree(graph, start, as_graph=True) try: next(graph_tool.topology.all_paths(a, b)) return True except StopIteration: return False This is without (the path search runs in Python, not that much LOCs but more difficult to understand in my opinion): dom_tree = graph_tool.topology.dominator_tree(graph, start, as_graph=True) while b: if a == b: return True b = dom_tree[b] return False Best, Gerion