Approximating minimum cut with bounded size

  • Authors:
  • Giulia Galbiati

  • Affiliations:
  • Dipartimento di Informatica e Sistemistica, Università degli Studi di Pavia, Pavia, Italy

  • Venue:
  • INOC'11 Proceedings of the 5th international conference on Network optimization
  • Year:
  • 2011

Quantified Score

Hi-index 0.00

Visualization

Abstract

We present the Minimum Cut with Bounded Size problem and two efficient algorithms for its solution. In this problem we want to partition the n vertices of a edge-weighted graph into two sets S and T, with S including a given source s, T a given sink t, and with |S| bounded by a given threshold B, so as to minimize the weight δ (S) of the edges crossing the cut (S,T). If B is equal to n-1 the problem is well-known to be solvable in polynomial time, but for general B it becomes NP-hard. The first algorithm is randomized and, for each ε 0, it returns, with high probability, a solution S having a weight within ratio (1+ εB/logn) of the optimum. The second algorithm is a deterministic bicriteria algorithm which can return a solution violating the cardinality constraint within a specified ratio; precisely, for each 0 S having either (1) a weight within ratio 1/1-γ of the optimum or (2) optimum weight but cardinality |S|≤ = B/γ, and hence it violates the constraint by a factor at most 1/γ.