Removing and Adding Edges for the Traveling Salesman Problem

We present a framework for approximating the metric TSP based on a novel use of matchings. Traditionally, matchings have been used to add edges to make a given graph Eulerian, whereas our approach also allows for the removal of certain edges leading to a decreased cost. For the TSP on graphic metrics (graph-TSP), we show that the approach gives a 1.461-approximation algorithm with respect to the Held-Karp lower bound. For graph-TSP restricted either to half-integral solutions to the Held-Karp relaxation or to a class of graphs that contains subcubic and claw-free graphs, we show that the integrality gap of the Held-Karp relaxation matches the conjectured ratio 4/3. The framework also allows for generalizations in a natural way and leads to analogous results for the s, t-path traveling salesman problem on graphic metrics where the start and end vertices are prespecified.


Published in:
Journal Of The Acm, 63, 1, 2
Year:
2016
Publisher:
New York, Assoc Computing Machinery
ISSN:
0004-5411
Keywords:
Laboratories:




 Record created 2016-07-19, last modified 2018-03-17


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