HiveBrain v1.2.0
Get Started
← Back to all entries
patternMinor

Does real linear programming produce bipartite perfect matching using maxflow reduction?

Submitted by: @import:stackexchange-cs··
0
Viewed 0 times
maxflowreallinearproduceprogrammingperfectbipartitereductionusingdoes

Problem

Given a bipartite graph the standard reduction to max flow is with the construction similar to following diagram:

We can formulate max flow as an linear programming problem with integer variables in latter.

-
If we do not use integer variables does solving for maxflow in linear programming formulation with only real variables still produce valid perfect matching of given graph?

-
Is there a formal proof of this?

Solution

Let us consider $K_{2,2}$, the complete bipartite graph with two vertices on either side. A valid max flow sends $1/2$ units of flow across each edge of the bipartite graph. This gives a negative answer to your first question.

On the other hand, the integral flow theorem guarantees that there exists an integral max flow, and such a max flow can be found algorithmically. An integral max flow does correspond to a maximum matching.

Context

StackExchange Computer Science Q#109743, answer score: 3

Revisions (0)

No revisions yet.