Journal Articles
Published
- A.N. Letchford & M.M. Sørensen (2025) New facets of the clique
partitioning polytope. Oper. Res. Lett., 59, article 107242.
(open access link)
- A.N. Letchford & L. Cheng (2024) On a variant of the change-making problem.
Oper. Res. Lett., 57, article 107165.
(open access link)
- L. Galli A.N. Letchford (2024) On upper bounds for the multiple knapsack
assignment problem. Oper. Res. Lett., 54, article 107104.
(open access link)
- F. Petropoulos et al. (2024) Operational research: methods and applications.
J. Oper. Res. Soc., 75(3), 423-617.
(open access link)
- M.M. Sørensen & A.N. Letchford (2024) CP-Lib: Benchmark instances of
the clique partitioning problem. Math. Program. Comput., 16(1), 93–111.
(PDF)
- K. Kaparis, A.N. Letchford & I. Mourtos (2023) On cut polytopes and graph
minors. Discr. Optim., 50, article 100807.
(PDF)
- M.A. Boschetti, A.N. Letchford & V. Maniezzo (2023) Matheuristics: survey and
synthesis. Int. Trans. Oper. Res., 30(6), 2840–2866.
(open access link)
- 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)
- 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)
- 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)
- 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)
- 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)
- 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)
- 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)
- 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)
- 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)
- 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)
- L. Galli & A.N. Letchford (2021) Valid inequalities for quadratic optimisation with
domain constraints. Discr. Optim., 41, article 100661.
(PDF)
- L. Galli & A.N. Letchford (2021) A separation algorithm for the simple plant location
problem. Oper. Res. Lett., 49(4), 610–615.
(PDF)
- A.N. Letchford & P. Ventura (2021) Strengthened clique-family inequalities for the
stable set polytope. Oper. Res. Lett., 49(4), 586–589.
(PDF)
- 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)
- 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)
- A.N. Letchford & A.N. Vu (2021) Facets from gadgets. Math. Program.,
185(1–2), 297–314. (PDF)
- A.N. Letchford, F. Rossi & S. Smriglio (2020) The stable set problem: clique and nodal
inequalities revisited. Comput. Oper. Res., 123, article 105024.
(PDF)
- A.N. Letchford & G. Souli (2020) Lifting the knapsack cover inequalities for the
knapsack polytope. Oper. Res. Lett., 48(5), 607–611.
(PDF)
- K. Kaparis, A.N. Letchford & Y. Mourtos (2020) On matroid parity and matching
polytopes. Discr. Appl. Math., 284, 322–331.
(PDF)
- T. Bektas & A.N. Letchford (2020) Using
ℓp norms for fairness in combinatorial
optimisation. Comput. Oper. Res., 120, article 104975.
(PDF)
- 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)
- 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)
- 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)
- 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) © Elsevier.
- 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)
- 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) © Elsevier.
- 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) © Elsevier.
- A.N. Letchford & A.J. Parkes (2018) A guide to conic optimisation and its applications.
RAIRO-OR, 52(4), 1087–1106. (PDF)
© EDP Sciences.
- 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.
- 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.
- 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.
- 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.
- J. Fairbrother & A.N. Letchford (2017) Projection results for the k-partition
problem. Discr. Optim., 26, 97–111.
(PDF)
- 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)
- 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)
- L. Galli & A.N. Letchford (2017) On the Lovász theta function and some
variants. Discr. Optim., 25, 159–174.
(PDF)
- 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)
- 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)
- 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)
- A.N. Letchford & S.D. Nasiri (2015) The Steiner travelling salesman problem with
correlated costs. Eur. J. Oper. Res., 245(1), 62–69.
(PDF)
- 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)
- I. Aliev & A.N. Letchford (2014) Iterated Chvátal-Gomory cuts and the geometry
of numbers. SIAM J. Optim., 24(3), 1294–1312.
(PDF)
- A.N. Letchford & M.M. Sørensen (2014) A new separation algorithm for the
Boolean quadric and cut polytopes. Discr. Optim., 14, 61–71.
(PDF)
- 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)
- 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)
- F. Djeumou Fomeni & A.N. Letchford (2014) A dynamic programming heuristic for the
quadratic knapsack problem. INFORMS J. Comput., 26(1), 173–182.
(PDF)
- 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)
- S. Burer & A.N. Letchford (2014) Unbounded convex sets for non-convex mixed-integer
quadratic programming. Math. Program., 143(1–2), 231–256.
(PDF)
- 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)
- 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)
- 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)
- 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)
- A.N. Letchford & M.M. Sørensen (2012) Binary positive semidefinite matrices and
associated integer polytopes. Math. Program., 131(1–2), 253–271.
(PDF)
- 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)
- 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)
- 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)
- C. Feremans, M. Labbé, A.N. Letchford & J.J. Salazar (2011) Generalised network
design polyhedra. Networks, 58(2), 125–136.
(PDF)
- 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)
- A. Caprara, A.N. Letchford & J.J. Salazar (2011) Decorous lower bounds for minimum
linear arrangement. INFORMS J. Comput., 23(1), 26–40.
(PDF)
- 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)
- L. Galli & A.N. Letchford (2010) Small bipartite subgraph polytopes. Oper. Res.
Lett., 38(5), 337–340. (PDF)
- K. Kaparis & A.N. Letchford (2010) Separation algorithms for 0-1 knapsack polytopes.
Math. Program., 124(1–2), 69–91.
(PDF)
- A. Caprara & A.N. Letchford (2010) New techniques for cost sharing in combinatorial
optimization games. Math. Program., 124(1–2), 93–118.
(PDF)
- S. Burer & A.N. Letchford (2009) On non-convex quadratic programming with box
constraints. SIAM J. Optim., 20(2), 1073–1089.
(PDF)
- 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)
- 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)
- 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)
- 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)
- 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)
- A.N. Letchford & N.A. Pearson (2008) Good triangulations yield good tours.
Comput. Oper. Res., 35(2), 638–647.
(PDF)
- 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)
- 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)
- M. Giandomenico & A.N. Letchford (2006) Exploring the relationship between max-cut and
stable set relaxations. Math. Program., 106(1), 159–175.
(PDF)
- A.N. Letchford & J.J. Salazar (2006) Projection results for vehicle routing.
Math. Program., 105(2–3), 251–274.
(PDF)
- 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)
- 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)
- A.N. Letchford & A. Lodi (2003) Primal separation algorithms. 4OR, 1(3),
209–224. (PDF)
- A.N. Letchford (2003) Binary clutter inequalities for integer programs. Math.
Program., 98(1–3), 201–221.
(PDF)
- A. Caprara & A.N. Letchford (2003) On the separation of split cuts and related
inequalities. Math. Program., 94(2–3), 279–294.
(PDF)
- 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)
- A.N. Letchford & A. Lodi (2002) Primal cutting plane algorithms revisited. Math.
Meth. Oper. Res., 56(1), 67–81.
(PDF)
- A.N. Letchford (2002) Totally tight Chvátal-Gomory cuts. Oper. Res. Lett.,
30(2), 71–73. (PDF)
- A.N. Letchford & A. Lodi (2002) Strengthening Chvátal-Gomory cuts and Gomory
fractional cuts Oper. Res. Lett., 30(2), 74–82.
(PDF)
- A.N. Letchford (2001) On disjunctive cuts for combinatorial optimization. J. Comb.
Optim., 5(3), 299–315. (PDF)
- A.N. Letchford & A. Amaral (2001) Analysis of upper bounds for the pallet loading
problem. Eur. J. Oper. Res., 132(3), 582–593.
(PDF)
- 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)
- A.N. Letchford (2000) Separating a superclass of comb inequalities in planar graphs.
Math. Oper. Res., 25(3), 443–454.
(PDF)
- A. Caprara, M. Fischetti & A.N. Letchford (2000) On the separation of maximally
violated mod-k cuts. Math. Program., 87(1), 37–56.
(PDF)
- A.N. Letchford (1999) The general routing polyhedron: a unifying framework.
Eur. J. Oper. Res., 112(1), 122–133.
(PDF)
- A.N. Letchford & R.W. Eglese (1998) The rural postman problem with deadline
classes. Eur. J. Oper. Res., 105(3), 390–400.
(PDF)
- 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)
- A.N. Letchford (1997) New inequalities for the general routing problem. Eur.
J. Oper. Res., 96(2), 317–322. (PDF)
- A.N. Letchford (1996) Allocation of school bus contracts by integer programming.
J. Oper. Res. Soc., 47(3), 369–372.
(PDF)
Submitted
- With S. Cáceres Gelvez & T.H. Dang: MIP-based local search for the
permutation flowshop problem. Submitted to Comput. Oper. Res. February 2025.
- With L. Galli: On a hierarchy of integer quadratic programming polytopes.
Submitted to ODS 2025 February 2025.
- With L. Durrell & T.H. Dang: Improving the semi-Lagrangian relaxation approach
to the simple plant location problem. Submitted to Comput. Oper. Res. January
2025.
Last update: February 2025.
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Adam N. Letchford