Journal Articles

Published

1. M.A. Boschetti, A.N. Letchford & V. Maniezzo (2023) Matheuristics: survey and synthesis. Int. Trans. Oper. Res., 30(6), 2840–2866. (open access link)
2. S. Cáceres Gelvez, T.H. Dang & A.N. Letchford (2023) On some lower bounds for the permutation flowshop problem. Comput. Oper. Res., 159, article 106320. (open access link)
3. O. Cruz-Mejía & A.N. Letchford (2023) A survey on exact algorithms for the maximum flow and minimum-cost flow problems. Networks, 82(2), 167–176. (open access link)
4. B. Boyaci, T.H. Dang & A.N. Letchford (2023) Fast upper and lower bounds for a large-scale real-world arc routing problem. Networks, 81(1), 107–124. (open access link)
5. B. Boyaci, T.H. Dang & A.N. Letchford (2023) Improving a constructive heuristic for the general routing problem. Networks, 81(1), 93–106. (open access link)
6. T. Dokka, A.N. Letchford & M.H. Mansoor (2022) Revisiting surrogate relaxation for the multidimensional knapsack problem. Oper. Res. Lett., 50(6), 674–678. (open access link)
7. C. Liu, A.N. Letchford & I. Svetunkov (2022) Newsvendor problems: an integrated method for estimation and optimisation. Eur. J. Oper. Res., 300(2), 590–601. (PDF)
8. F. Djeumou Fomeni, K. Kaparis & A.N. Letchford (2022) A cut-and-branch algorithm for the quadratic knapsack problem. Discr. Optim., 44(2), article 100579. (PDF)
9. K. Kaparis, A.N. Letchford & Y. Mourtos (2022) Generalised 2-circulant inequalities for the max-cut problem. Oper. Res. Lett., 50(2), 122–128. (PDF)
10. B. Boyaci, T.H. Dang & A.N. Letchford (2022) On matchings, T-joins and arc routing in road networks. Networks, 79(1), 20–31. (open access link)
11. A.N. Letchford, Q. Ni & Z. Zhong (2021) Bi-perspective functions for mixed-integer fractional programs with indicator variables. Math. Program., 190(1-2), 39–55. (open access link)
12. L. Galli & A.N. Letchford (2021) Valid inequalities for quadratic optimisation with domain constraints. Discr. Optim., 41, article 100661. (PDF)
13. L. Galli & A.N. Letchford (2021) A separation algorithm for the simple plant location problem. Oper. Res. Lett., 49(4), 610–615. (PDF)
14. A.N. Letchford & P. Ventura (2021) Strengthened clique-family inequalities for the stable set polytope. Oper. Res. Lett., 49(4), 586–589. (PDF)
15. T. Dokka, A.N. Letchford & M.H. Mansoor (2021) On the complexity of surrogate and group relaxation for integer linear programs. Oper. Res. Lett., 49(4), 530–534. (PDF)
16. B. Boyaci, T.H. Dang & A.N. Letchford (2021) Vehicle routing on road networks: how good is Euclidean approximation? Comput. Oper. Res., 129, article 105197. (PDF)
17. A.N. Letchford & A.N. Vu (2021) Facets from gadgets. Math. Program., 185(1–2), 297–314. (PDF)
18. A.N. Letchford, F. Rossi & S. Smriglio (2020) The stable set problem: clique and nodal inequalities revisited. Comput. Oper. Res., 123, article 105024. (PDF)
19. A.N. Letchford & G. Souli (2020) Lifting the knapsack cover inequalities for the knapsack polytope. Oper. Res. Lett., 48(5), 607–611. (PDF)
20. K. Kaparis, A.N. Letchford & Y. Mourtos (2020) On matroid parity and matching polytopes. Discr. Appl. Math., 284, 322–331. (PDF)
21. T. Bektas & A.N. Letchford (2020) Using ℓ^p norms for fairness in combinatorial optimisation. Comput. Oper. Res., 120, article 104975. (PDF)
22. A.N. Letchford & G. Souli (2020) Valid inequalities for mixed-integer programmes with fixed charges on sets of variables. Oper. Res. Lett., 48(3), 240–244. (PDF)
23. K. Glazebrook, J.A. Grant, D.S. Leslie, R. Szechtman & A.N. Letchford (2020) Adaptive policies for perimeter surveillance problems. Eur. J. Oper. Res., 283(1), 265–278. (open access link)
24. A.N. Letchford, Q. Ni & Z. Zhong (2020) A heuristic for fair dynamic resource allocation in overloaded OFDMA systems. J. of Heuristics, 26(1), 21–32. (PDF)
25. A.N. Letchford & G. Souli (2019) New valid inequalities for the fixed-charge and single-node flow polytopes. Oper. Res. Lett., 47(5), 353–357. (PDF)
26. P. Fearnhead, R. Maidstone & A.N. Letchford (2019) Detecting changes in slope with an L₀ penalty. J. Comput. Graph. Stat., 28(2), 265–275. (open access link)
27. A.N. Letchford & G. Souli (2019) On lifted cover inequalities: a new lifting procedure with unusual properties. Oper. Res. Lett., 47(2), 83–87. (PDF)
28. A.N. Letchford & J.J. Salazar (2019) The capacitated vehicle routing problem: stronger bounds in pseudo-polynomial time. Eur. J. Oper. Res., 272(1), 24–31. (PDF)
29. A.N. Letchford & A.J. Parkes (2018) A guide to conic optimisation and its applications. RAIRO-OR, 52(4), 1087–1106. (PDF) © EDP Sciences.
30. L. Galli & A.N. Letchford (2018) A binarisation heuristic for non-convex quadratic programming with box constraints. Oper. Res. Lett., 46(5), 529–533. (PDF) © Elsevier.
31. K. Kaparis & A.N. Letchford (2018) A note on the 2-circulant inequalities for the max-cut problem. Oper. Res. Lett., 46(4), 443–447. (PDF) © Elsevier.
32. L. Galli, A.N. Letchford & S.J. Miller (2018) New valid inequalities and facets for the simple plant location problem. Eur. J. Oper. Res., 269(3), 824–833. (PDF) © Elsevier.
33. J. Fairbrother, A.N. Letchford & K. Briggs (2018) A two-level graph partitioning problem arising in mobile wireless communications. Comput. Optim. Appl., 69(3), 653–676. (PDF) © Springer.
34. J. Fairbrother & A.N. Letchford (2017) Projection results for the k-partition problem. Discr. Optim., 26, 97–111. (PDF) © Elsevier.
35. A.N. Letchford & D.J. Grainger (2017) A note on representations of linear inequalities in non-convex mixed-integer quadratic programs. Oper. Res. Lett., 45(6), 631–634. (PDF) © Elsevier.
36. A.N. Letchford, Q. Ni & Z. Zhong (2017) An exact algorithm for a resource allocation problem in mobile wireless communications. Comput. Optim. Appl., 68(2), 193–208. (PDF) © Springer.
37. L. Galli & A.N. Letchford (2017) On the Lovász theta function and some variants. Discr. Optim., 25, 159–174. (PDF) © Elsevier.
38. A.N. Letchford & J.J. Salazar (2016) Stronger multi-commodity flow formulations of the (capacitated) sequential ordering problem. Eur. J. Oper. Res., 251(1), 74–84. (PDF) © Elsevier.
39. M. Giandomenico, A.N. Letchford, F. Rossi & S. Smriglio (2015) Ellipsoidal relaxations of the stable set problem: theory and algorithms. SIAM J. Optim., 25(3), 1944–1963. (PDF) © SIAM.
40. F. Djeumou Fomeni, K. Kaparis & A.N. Letchford (2015) Cutting planes for RLT relaxations of mixed 0-1 polynomial programs. Math. Program., 151(2), 639–658. (PDF) © Springer.
41. A.N. Letchford & S.D. Nasiri (2015) The Steiner travelling salesman problem with correlated costs. Eur. J. Oper. Res., 245(1), 62–69. (PDF) © Springer.
42. A.N. Letchford & J.J. Salazar (2015) Stronger multi-commodity flow formulations of the capacitated vehicle routing problem. Eur. J. Oper. Res., 244(3), 730–738. (PDF) © Elsevier.
43. I. Aliev & A.N. Letchford (2014) Iterated Chvátal-Gomory cuts and the geometry of numbers. SIAM J. Optim., 24(3), 1294–1312. (PDF) © SIAM.
44. A.N. Letchford & M.M. Sørensen (2014) A new separation algorithm for the Boolean quadric and cut polytopes. Discr. Optim., 14, 61–71. (PDF) © Elsevier.
45. A.N. Letchford, S.D. Nasiri & A. Oukil (2014) Pricing routines for vehicle routing with time windows on road networks. Comput. Oper. Res., 51, 331–337. (PDF) © Elsevier.
46. L. Galli & A.N. Letchford (2014) A compact variant of the QCR method for quadratically constrained quadratic 0-1 programs. Optim. Lett., 8(4), 1213–1224. (PDF) © Springer.
47. F. Djeumou Fomeni & A.N. Letchford (2014) A dynamic programming heuristic for the quadratic knapsack problem. INFORMS J. Comput., 26(1), 173–182. (PDF) © INFORMS.
48. A.N. Letchford & S.J. Miller (2014) An aggressive reduction scheme for the simple plant location problem. Eur. J. Oper. Res., 234(3), 674–682. (PDF) © Elsevier.
49. S. Burer & A.N. Letchford (2014) Unbounded convex sets for non-convex mixed-integer quadratic programming. Math. Program., 143(1–2), 231–256. (PDF) © Springer.
50. A.R.S. Amaral & A.N. Letchford (2013) A polyhedral approach to the single-row facility layout problem. Math. Program., 141(1–2), 453–477. (PDF) © Springer.
51. A.N. Letchford, S.D. Nasiri & D.O. Theis (2013) Compact formulations of the Steiner TSP and related problems. Eur. J. Oper. Res., 228(1), 83–92. (PDF) © Elsevier.
52. S. Burer & A.N. Letchford (2012) Non-convex mixed-integer nonlinear programming: a survey. Surveys in Oper. Res. and Mgmt. Sci., 17(2), 97–106. (PDF) © Elsevier.
53. L. Galli, K. Kaparis & A.N. Letchford (2012) Complexity results for the gap inequalities for the max-cut problem. Oper. Res. Lett., 40(3), 149–152. ( PDF) © Elsevier.
54. A.N. Letchford & M.M. Sørensen (2012) Binary positive semidefinite matrices and associated integer polytopes. Math. Program., 131(1–2), 253–271. (PDF) © Springer.
55. A.N. Letchford & S.J. Miller (2012) Fast bounding procedures for large instances of the simple plant location problem. Comput. Oper. Res., 39(5), 985–990. (PDF) © Elsevier.
56. A.N. Letchford, S. Pokutta & A.S. Schulz (2011) On the membership problem for the {0, 1/2}-closure. Oper. Res. Lett., 39(5), 301–304. (PDF) © Elsevier.
57. L. Galli, K. Kaparis & A.N. Letchford (2011) Gap inequalities for non-convex mixed-integer quadratic programs. Oper. Res. Lett., 39(5), 297–300. (PDF) © Elsevier.
58. C. Feremans, M. Labbé, A.N. Letchford & J.J. Salazar (2011) Generalised network design polyhedra. Networks, 58(2), 125–136. (PDF) © Wiley.
59. M. Fortini, A.N. Letchford, A. Lodi & K.M. Wenger (2011) Computing compatible tours for the symmetric traveling salesman problem. Math. Program. Comput., 3(1), 59–78. (PDF) © Springer.
60. A. Caprara, A.N. Letchford & J.J. Salazar (2011) Decorous lower bounds for minimum linear arrangement. INFORMS J. Comput., 23(1), 26–40. (PDF) © INFORMS.
61. A.N. Letchford, G. Reinelt, H. Seitz & D.O. Theis (2010) On a class of metrics related to graph layout problems. Lin. Alg. Appl., 433(11–12), 1760–1777. (PDF) © Elsevier.
62. L. Galli & A.N. Letchford (2010) Small bipartite subgraph polytopes. Oper. Res. Lett., 38(5), 337–340. (PDF) © Elsevier.
63. K. Kaparis & A.N. Letchford (2010) Separation algorithms for 0-1 knapsack polytopes. Math. Program., 124(1–2), 69–91. (PDF) © Springer.
64. A. Caprara & A.N. Letchford (2010) New techniques for cost sharing in combinatorial optimization games. Math. Program., 124(1–2), 93–118. (PDF) © Springer.
65. S. Burer & A.N. Letchford (2009) On non-convex quadratic programming with box constraints. SIAM J. Optim., 20(2), 1073–1089. (PDF) © SIAM.
66. M. Giandomenico, A.N. Letchford, F. Rossi & S. Smriglio (2009) An application of the Lovász-Schrijver M(K,K) operator to the stable set problem. Math. Program., 120(2), 381–401. (PDF) © Springer.
67. A.N. Letchford & A. Oukil (2009) Exploiting sparsity in pricing routines for the capacitated arc routing problem. Comput. Oper. Res., 36(7), 2320–2327. (PDF) © Elsevier.
68. A.N. Letchford, G. Reinelt & D.O. Theis (2008) Odd minimum cut-sets and b-matchings revisited. SIAM J. Discr. Math., 22(4), 1480–1487. (PDF) © SIAM.
69. A.N. Letchford & N.A. Pearson (2008) Exploiting planarity in separation routines for the symmetric traveling salesman problem. Discr. Optim., 5(2), 220–230. (PDF) © Elsevier.
70. K. Kaparis & A.N. Letchford (2008) Local and global lifted cover inequalities for the multidimensional knapsack problem. Eur. J. Oper. Res., 186(1), 91–103. (PDF) © Elsevier.
71. A.N. Letchford & N.A. Pearson (2008) Good triangulations yield good tours. Comput. Oper. Res., 35(2), 638–647. (PDF) © Elsevier.
72. A.N. Letchford, J. Lysgaard & R.W. Eglese (2007) A branch-and-cut algorithm for the capacitated open vehicle routing problem. J. Oper. Res. Soc., 58(12), 1642–1651. (PDF) © Palgrave.
73. L.K. Fleischer, A.N. Letchford & A. Lodi (2006) Polynomial-time separation of a superclass of simple comb inequalities. Math. Oper. Res., 31(4), 696–713. (PDF) © INFORMS.
74. M. Giandomenico & A.N. Letchford (2006) Exploring the relationship between max-cut and stable set relaxations. Math. Program., 106(1), 159–175. (PDF) © Springer.
75. A.N. Letchford & J.J. Salazar (2006) Projection results for vehicle routing. Math. Program., 105(2–3), 251–274. (PDF) © Springer.
76. A.N. Letchford & N.A. Pearson (2005) A fast algorithm for minimum weight odd circuits and cuts in planar graphs. Oper. Res. Lett., 33(6), 625–628. (PDF) © Elsevier.
77. J. Lysgaard, A.N. Letchford & R.W. Eglese (2004) A new branch-and-cut algorithm for the capacitated vehicle routing problem. Math. Program., 100(2), 423–445. (PDF) © Springer.
78. A.N. Letchford & A. Lodi (2003) Primal separation algorithms. 4OR, 1(3), 209–224. (PDF) © Springer.
79. A.N. Letchford (2003) Binary clutter inequalities for integer programs. Math. Program., 98(1–3), 201–221. (PDF) © Springer.
80. A. Caprara & A.N. Letchford (2003) On the separation of split cuts and related inequalities. Math. Program., 94(2–3), 279–294. (PDF) © Springer.
81. A.N. Letchford, R.W. Eglese & J. Lysgaard (2002) Multistars, partial multistars and the capacitated vehicle routing problem. Math. Program., 94(1), 21–40. (PDF) © Springer.
82. A.N. Letchford & A. Lodi (2002) Primal cutting plane algorithms revisited. Math. Meth. Oper. Res., 56(1), 67–81. (PDF) © Springer.
83. A.N. Letchford (2002) Totally tight Chvátal-Gomory cuts. Oper. Res. Lett., 30(2), 71–73. (PDF) © Elsevier.
84. A.N. Letchford & A. Lodi (2002) Strengthening Chvátal-Gomory cuts and Gomory fractional cuts. Oper. Res. Lett., 30(2), 74–82. (PDF) © Elsevier.
85. A.N. Letchford (2001) On disjunctive cuts for combinatorial optimization. J. Comb. Optim., 5(3), 299–315. (PDF) © Springer.
86. A.N. Letchford & A. Amaral (2001) Analysis of upper bounds for the pallet loading problem. Eur. J. Oper. Res., 132(3), 582–593. (PDF) © Elsevier.
87. A. Corberán, A.N. Letchford & J.M. Sanchis (2001) A cutting plane algorithm for the general routing problem. Math. Program., 90(2), 291–316. (PDF) © Springer.
88. A.N. Letchford (2000) Separating a superclass of comb inequalities in planar graphs. Math. Oper. Res., 25(3), 443–454. (PDF) © INFORMS.
89. A. Caprara, M. Fischetti & A.N. Letchford (2000) On the separation of maximally violated mod-k cuts. Math. Program., 87(1), 37–56. (PDF) © Springer.
90. A.N. Letchford (1999) The general routing polyhedron: a unifying framework. Eur. J. Oper. Res., 112(1), 122–133. (PDF) © Elsevier.
91. A.N. Letchford & R.W. Eglese (1998) The rural postman problem with deadline classes. Eur. J. Oper. Res., 105(3), 390–400. (PDF) © Elsevier.
92. D.D. Clarke & A.N. Letchford (1998) Action rules extracted by machine induction from feature-coded self-reports. J. Soc. Beh. Pers., 13(1), 33–50. (PDF) © Select Press.
93. A.N. Letchford (1997) New inequalities for the general routing problem. Eur. J. Oper. Res., 96(2), 317–322. (PDF) © Elsevier.
94. A.N. Letchford (1996) Allocation of school bus contracts by integer programming. J. Oper. Res. Soc., 47(3), 369–372. (PDF) © Palgrave.

Accepted

• With F. Petropoulos and others: Operational research: methods and applications. Accepted by J. Oper. Res. Soc., August 2023.

Revised

• With M.M. Sørensen: CP-Lib: Benchmark instances of the clique partitioning problem. Submitted to Math. Program. Comput. November 2022. Revised June 2023. (PDF)

Submitted

• With C. Liu & I. Svetunkov: Naive newsvendor adjustments: are they always detrimental? Submitted to Oper. Res. Lett., August 2023. (PDF)
• With K. Kaparis & I. Mourtos: On cut polytopes and graph minors. Submitted to Discr. Optim., July 2023. (PDF)
• With L. Galli: On upper bounds for the multiple knapsack assignment problem. Submitted to Oper. Res. Lett., July 2023. (PDF)

Last update: August 2023.

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