Reconstructing edge-disjoint paths, a tighter analysis
This is a small improvement of the analysis of [1], this assume you already read that paper.
Given a simple undirected graph of vertices and edges, construct a data structure such that we can query two vertices and , and it returns the maximum edge disjoint paths between and .
We let to be the time to compute -maximum flow on a undirected unit capacity graph.
The current state of art in the article is:
- Proprocessing time .
- space.
- query time.
We can improve this by having a tighter analysis.
First, if and be -edge disjoint path from to and to respectively. Let be the number of edges in , then there exist an algorithm to output -edge disjoint path from to in time. One can see this by update section of their paper by using a stable matching algorithm without the dummy edges, because this is just stable matching with incomplete lists[2].
Second, acyclic flow of value uses only edges(Theorem 3.1 in [3]), therefore we do not have to store any non-acyclic flows. This also speed up all computations because the number of edges are smaller.
Third, we can use space and get a query time of . In fact there is a time space trade off [4].
Thus finally, we get
- Proprocessing time .
- space.
- query time.
With even better analysis, we can obtain the following [5].
- Proprocessing time .
- space.
- query time for a edge disjoint path from to .