Abstract
The comb inequalities are a well-known class of facet-inducing inequalities for the Traveling Salesman Problem, defined in terms of certain vertex sets called the handle and the teeth. We say that a comb inequality is simple if the following holds for each tooth: either the intersection of the tooth with the handle has cardinality one, or the part of the tooth outside the handle has cardinality one, or both. The simple comb inequalities generalize the classical 2-matching inequalities of Edmonds, and also the so-called Chvátal comb inequalities.
In 1982, Padberg and Rao [29] gave a polynomial-time algorithm for separating the 2-matching inequalities — i.e., for testing if a given fractional solution to an LP relaxation violates a 2-matching inequality. We extend this significantly by giving a polynomial-time algorithm for separating the simple comb inequalities. The key is a result due to Caprara and Fischetti.
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References
D. Applegate, R.E. Bixby, V. Chvátal & W. Cook (1995) Finding cuts in the TSP (a preliminary report). Technical Report 95-05, DIMACS, Rutgers University, New Brunswick, NJ.
A. Caprara & M. Fischetti (1996) 0,1/2-Chvátal-Gomory cuts. Math. Program. 74, 221–235.
A. Caprara, M. Fischetti & A.N. Letchford (2000) On the separation of maximally violated mod-k cuts. Math. Program. 87, 37–56.
A. Caprara & A.N. Letchford (2001) On the separation of split cuts and related inequalities. To appear in Math. Program.
R. Carr (1997) Separating clique trees and bipartition inequalities having a fixed number of handles and teeth in polynomial time. Math. Oper. Res. 22, 257–265.
V. Chvátal (1973) Edmonds polytopes and weakly Hamiltonian graphs. Math. Program. 5, 29–40.
G.B. Dantzig, D.R. Fulkerson & S.M. Johnson (1954) Solution of a large-scale traveling salesman problem. Oper. Res. 2, 393–410.
J. Edmonds (1965) Maximum matching and a polyhedron with 0-1 vertices. J. Res. Nat. Bur. Standards 69B, 125–130.
L. Fleischer & É. Tardos (1999) Separating maximally violated comb inequalities in planar graphs. Math. Oper. Res. 24, 130–148.
J. Fonlupt & D. Naddef (1992) The traveling salesman problem in graphs with excluded minors. Math. Program. 53, 147–172.
M.X. Goemans (1995) Worst-case comparison of valid inequalities for the TSP. Math. Program. 69, 335–349.
A.V. Goldberg & R.E. Tarjan (1988) A new approach to the maximum flow problem. J. of the A.C.M. 35, 921–940.
M. Grötschel & O. Holland (1987) A cutting plane algorithm for minimum perfect 2-matching. Computing 39, 327–344.
M. Grötschel, L. Lovász & A.J. Schrijver (1988) Geometric Algorithms and Combinatorial Optimization. Wiley: New York.
M. Grötschel & M.W. Padberg (1979) On the symmetric traveling salesman problem I: inequalities. Math. Program. 16, 265–280.
M. Grötschel & M.W. Padberg (1979) On the symmetric traveling salesman problem II: lifting theorems and facets. Math. Program. 16, 281–302.
M. Grötschel & K. Truemper (1989) Decomposition and optimization over cycles in binary matroids. J. Comb. Th. (B) 46, 306–337.
M.R. Hensinger & D.P. Williamson (1996) On the number of small cuts in a graph. Inf. Proc. Lett. 59, 41–44.
M. Jünger, G. Reinelt, G. Rinaldi (1995) The traveling salesman problem. In M. Ball, T. Magnanti, C. Monma & G. Nemhauser (eds.). Network Models, Handbooks in Operations Research and Management Science, 7, Elsevier Publisher B.V., Amsterdam, 225–330.
M. Jünger, G. Reinelt & G. Rinaldi (1997) The traveling salesman problem. In M. Dell’Amico, F. Maffioli & S. Martello (eds.) Annotated Bibliographies in Combinatorial Optimization. Chichester, Wiley, 199–221.
A.N. Letchford (2000) Separating a superclass of comb inequalities in planar graphs. Math. Oper. Res. 25, 443–454.
D. Naddef (2001) Polyhedral theory and branch-and-cut algorithms for the symmetric TSP. In G. Gutin & A. Punnen (eds.), The Traveling Salesman Problem and its Variations. Kluwer Academic Publishers, 2002 (to appear).
D. Naddef & G. Rinaldi (1991) The symmetric traveling salesman polytope and its graphical relaxation: composition of valid inequalities. Math. Program. 51, 359–400.
D. Naddef & G. Rinaldi (1993) The graphical relaxation: a new framework for the symmetric traveling salesman polytope. Math. Program. 58, 53–88.
D. Naddef & S. Thienel (1998) Efficient separation routines for the symmetric traveling salesman problem I: general tools and comb separation. Working paper, LMC-IMAG, Grenoble.
H. Nagamochi, K. Nishimura and T. Ibaraki (1997) Computing all small cuts in undirected networks. SIAM Disc. Math. 10, 469–481.
G.L. Nemhauser and L.A. Wolsey (1988) Integer and Combinatorial Optimization. New York: Wiley.
M.W. Padberg & M. Grötschel (1985) Polyhedral computations. In E.L. Lawler, J.K. Lenstra, A.H.G. Rinnooy Kan & D.B. Schmoys (Eds.) The Traveling Salesman Problem. John Wiley & Sons, Chichester.
M.W. Padberg & M.R. Rao (1982) Odd minimum cut-sets and b-matchings. Math. Oper. Res. 7, 67–80.
M.W. Padberg & G. Rinaldi (1990) Facet identification for the symmetric traveling salesman polytope. Math. Program. 47, 219–257.
M.W. Padberg & G. Rinaldi (1991) A branch-and-cut algorithm for the resolution of large-scale symmetric traveling salesman problems. SIAM Rev. 33, 60–100.
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Letchford, A.N., Lodi, A. (2002). Polynomial-Time Separation of Simple Comb Inequalities. In: Cook, W.J., Schulz, A.S. (eds) Integer Programming and Combinatorial Optimization. IPCO 2002. Lecture Notes in Computer Science, vol 2337. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-47867-1_8
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DOI: https://doi.org/10.1007/3-540-47867-1_8
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