Items where Author is "Letchford, Adam"

Letchford, Adam and Soerensen, Michael (2025) New facets of the clique partitioning polytope. Operations Research Letters, 59: 107242. ISSN 0167-6377

Letchford, Adam and Cheng, Licong (2024) On a variant of the change-making problem. Operations Research Letters, 57: 107165. ISSN 0167-6377

Galli, Laura and Letchford, Adam (2024) On upper bounds for the multiple knapsack assignment problem. Operations Research Letters, 54: 107104. ISSN 0167-6377

Sorensen, Michael and Letchford, Adam (2024) CP-Lib: Benchmark instances of the clique partitioning problem. Mathematical Programming Computation, 16 (1): 1. pp. 93-111. ISSN 1867-2949

Eglese, Richard and Letchford, Adam (2024) Arc routing problems. In: Encyclopedia of Optimization :. Springer, Cham.

Randall, Matt and Letchford, Adam and Kheiri, Ahmed (2024) Putting the ping into online shopping: Dynamic Heuristics for Vehicle Routing and Slot Offering. PhD thesis, Lancaster University.

Boschetti, Marco and Letchford, Adam and Maniezzo, Vittorio (2023) Matheuristics : survey and synthesis. International Transactions in Operational Research, 30 (6). pp. 2840-2866. ISSN 0969-6016

Kaparis, Konstantinos and Letchford, Adam and Mourtos, Ioannis (2023) On cut polytopes and graph minors. Discrete Optimization, 50: 100807. ISSN 1572-5286

Letchford, Adam and Dang, Thu and Caceres Gelvez, Sebastian (2023) On some lower bounds for the permutation flowshop problem. Computers and Operations Research, 159: 106320. ISSN 0305-0548

Cruz Mejía, Oliverio and Letchford, Adam (2023) A survey on exact algorithms for the maximum flow and minimum-cost flow problems. Networks, 82 (2). pp. 167-176. ISSN 0028-3045

Tilley, Daniel and Letchford, Adam and Syntetos, Aris and Misener, Ruth and Liu, Karrie (2023) The 4th IMA and OR Society conference on the mathematics of operational research: thoughts from the committee. IFORS Newsletter, 18 (3). pp. 35-37.

Letchford, Adam and Liu, Karrie and Misener, Ruth and Syntetos, Aris and Tilley, Daniel (2023) The mathematics of operational research. Mathematics Today, 69 (4). p. 103.

Letchford, Adam (2023) On upper bounds for the multiple knapsack assignment problem. In: 4th IMA and OR Society Conference on Mathematics of Operational Research, 2023-04-27 - 2023-04-28, Conference Aston.

Boyacı, Burak and Dang, Thu and Letchford, Adam (2023) Fast upper and lower bounds for a large-scale real-world arc routing problem. Networks, 81 (1). pp. 107-124. ISSN 0028-3045

Boyacı, Burak and Dang, Thu and Letchford, Adam (2023) Improving a constructive heuristic for the general routing problem. Networks, 81 (1). pp. 93-106. ISSN 0028-3045

Liu, Congzheng and Letchford, Adam and Svetunkov, Ivan (2023) Extensions to Newsvendor Problems. PhD thesis, Lancaster University.

Dokka, Trivikram and Letchford, Adam and Mansoor, Hasan (2022) Revisiting surrogate relaxation for the multidimensional knapsack problem. Operations Research Letters, 50 (6). pp. 674-678. ISSN 0167-6377

Letchford, Adam (2022) On the multiple knapsack assignment problem. In: 2022 International Conference on Optimization and Decision Science, 2022-08-30 - 2022-09-02, Centro Didattico Morgagni.

Liu, Congzheng and Letchford, Adam and Svetunkov, Ivan (2022) Newsvendor problems : An integrated method for estimation and optimisation. European Journal of Operational Research, 300 (2). pp. 590-601. ISSN 0377-2217

Djeumou Fomeni, Franklin and Kaparis, Konstantinos and Letchford, Adam (2022) A cut-and-branch algorithm for the quadratic knapsack problem. Discrete Optimization, 44 (2): 100579. ISSN 1572-5286

Letchford, Adam (2022) The Boolean quadric polytope. In: The Quadratic Unconstrained Binary Optimization Problem : Theory, Algorithms, and Applications. Springer, Cham, Switzerland, pp. 97-120. ISBN 9783031045196

Kaparis, Konstantinos and Letchford, Adam and Mourtos, Ioannis (2022) Generalised 2-circulant inequalities for the max-cut problem. Operations Research Letters, 50 (2). pp. 122-128. ISSN 0167-6377

Boyacı, Burak and Dang, Thu and Letchford, Adam (2022) On matchings, T-joins and arc routing problems. Networks, 79 (1). pp. 20-31. ISSN 0028-3045

Mansoor, M Hasan and Letchford, Adam and Dokka Venkata Satyanaraya, Trivikram (2022) Combinatorial Optimisation : Relaxation, Duality and Heuristics. PhD thesis, Lancaster University.

Dang, Thu and Letchford, Adam and Boyaci, Burak (2022) Exact and Heuristic Approaches to Arc Routing Problems. PhD thesis, Lancaster University.

Letchford, Adam and Ni, Qiang and Zhong, Zhaoyu (2021) Biperspective functions for mixed-integer fractional programs with indicator variables. Mathematical Programming, 190 (1-2). pp. 39-55. ISSN 0025-5610

Galli, Laura and Letchford, Adam (2021) Valid inequalities for quadratic optimisation with domain constraints. Discrete Optimization, 41: 100661. ISSN 1572-5286

Fliege, Joerg and Letchford, Adam and Tilley, Daniel (2021) Maths of OR – Reflections from the Committee. Mathematics Today, 57 (4). p. 115.

Dokka, Trivikram and Letchford, Adam and Mansoor, Hasan (2021) On the complexity of surrogate and group relaxation for integer linear programs. Operations Research Letters, 49 (4). pp. 530-534. ISSN 0167-6377

Letchford, Adam and Ventura, Paolo (2021) Strengthened clique-family inequalities for the stable set polytope. Operations Research Letters, 49 (4). pp. 586-589. ISSN 0167-6377

Galli, Laura and Letchford, Adam (2021) A separation algorithm for the simple plant location problem. Operations Research Letters, 49 (4). pp. 610-615. ISSN 0167-6377

Boyacı, Burak and Dang, Thu and Letchford, Adam (2021) Vehicle routing on road networks : how good is Euclidean approximation? Computers and Operations Research, 129: 105197. ISSN 0305-0548

Letchford, Adam and Vu, Anh (2021) Facets from gadgets. Mathematical Programming, 185 (1-2). pp. 297-314. ISSN 0025-5610

Souli, Georgia and Letchford, Adam (2021) New valid inequalities for knapsack and fixed-charge problems. PhD thesis, Lancaster University.

Letchford, Adam and Rossi, Fabrizio and Smriglio, Stefano (2020) The stable set problem : clique and nodal inequalities revisited. Computers and Operations Research, 123: 105024. ISSN 0305-0548

Kaparis, Konstantinos and Letchford, Adam and Mourtos, Ioannis (2020) On matroid parity and matching polytopes. Discrete Applied Mathematics, 284. pp. 322-331. ISSN 0166-218X

Letchford, Adam and Souli, Georgia (2020) Lifting the knapsack cover inequalities for the knapsack polytope. Operations Research Letters, 48 (5). pp. 607-611. ISSN 0167-6377

Bektas, Tolga and Letchford, Adam (2020) Using ℓp-norms for fairness in combinatorial optimisation. Computers and Operations Research, 120: 104975. ISSN 0305-0548

Grant, James A. and Leslie, David S. and Glazebrook, Kevin and Szechtman, Roberto and Letchford, Adam (2020) Adaptive policies for perimeter surveillance problems. European Journal of Operational Research, 283 (1). pp. 265-278. ISSN 0377-2217

Letchford, Adam and Souli, Georgia (2020) Valid inequalities for mixed-integer programmes with fixed charges on sets of variables. Operations Research Letters, 48 (3). pp. 240-244. ISSN 0167-6377

Letchford, Adam and Ni, Qiang and Zhong, Zhaoyu (2020) A heuristic for fair dynamic resource allocation in over-loaded OFDMA systems. Journal of Heuristics, 26 (1). pp. 21-32. ISSN 1381-1231

Letchford, Adam and Souli, Georgia (2019) New valid inequalities for the fixed-charge and single-node flow polytopes. Operations Research Letters, 47 (5). pp. 353-357. ISSN 0167-6377

Letchford, Adam (2019) Convex hulls for mixed-integer quadratic programs with bounded variables. In: 61st Annual Conference of the Operational Research Society, 2019-09-03 - 2019-09-05, University of Kent.

Fearnhead, Paul and Maidstone, Robert and Letchford, Adam (2019) Detecting changes in slope with an L0 penalty. Journal of Computational and Graphical Statistics, 28 (2). pp. 265-275. ISSN 1061-8600

Letchford, Adam (2018) Bi-perspective cuts for mixed-integer fractional programs with indicator variables. In: 23rd International Symposium on Mathematical Programming, 2018-07-01 - 2018-07-06, University of Bordeaux.

Letchford, Adam (2018) A sum-of-squares approach to achieving fairness in combinatorial optimisation. In: International Symposium on Combinatorial Optimization, 2018-04-11 - 2018-04-13.

Zhong, Zhaoyu and Letchford, Adam and Ni, Qiang (2018) Optimal resource allocation In base stations for mobile wireless communications. PhD thesis, Lancaster University.

Letchford, Adam (2016) NATCOR : Ten years of doctoral training in OR. IFORS Newsletter, 10 (4). pp. 10-11.

Maidstone, Robert and Fearnhead, Paul and Letchford, Adam (2016) Efficient analysis of complex changepoint problems. PhD thesis, Lancaster University.

Letchford, Adam and Salazar Gonzalez, Juan Jose (2016) Stronger multi-commodity flow formulations of the (capacitated) sequential ordering problem. European Journal of Operational Research, 251 (1). pp. 74-84. ISSN 0377-2217

Letchford, Adam and Marecek, Jakub (2015) Review of "Integer Programming” by Conforti et al. Interfaces, 45 (5). pp. 481-482. ISSN 0092-2102

Letchford, Adam and Nasiri, Saeideh (2015) The Steiner travelling salesman problem with correlated costs. European Journal of Operational Research, 245 (1). 62–69. ISSN 0377-2217

Giandomenico, Monia and Letchford, Adam and Rossi, Fabrizio and Smriglio, Stefano (2015) Ellipsoidal relaxations of the stable set problem : theory and algorithms. SIAM Journal on Optimization, 25 (3). pp. 1944-1963. ISSN 1052-6234

Letchford, Adam and Salazar Gonzalez, Juan Jose (2015) Stronger multi-commodity flow formulations of the capacitated vehicle routing problem. European Journal of Operational Research, 244 (3). pp. 730-738. ISSN 0377-2217

Letchford, Adam and Lasserre, Jean B. and Parrilo, Pablo A. and Steurer, David (2015) Preface: The 2013 Newton Institute programme on polynomial optimisation. Mathematical Programming, 151 (2). 375–377. ISSN 0025-5610

Djeumou Fomeni, Franklin and Kaparis, Konstantinos and Letchford, Adam (2015) Cutting planes for RLT relaxations of mixed 0-1 polynomial programs. Mathematical Programming, 151 (2). 639–658. ISSN 0025-5610

Dehghan Nasiri, Saeideh and Letchford, Adam (2014) Vehicle routing on real road networks. PhD thesis, Lancaster University.

Letchford, Adam and Nasiri, Saeideh D. and Oukil, Amar (2014) Pricing routines for vehicle routing with time windows on road networks. Computers and Operations Research, 51. pp. 331-337. ISSN 0305-0548

Letchford, Adam and Sorensen, Michael M. (2014) A new separation algorithm for the Boolean quadric and cut polytopes. Discrete Optimization, 14. pp. 61-71. ISSN 1572-5286

Letchford, Adam and Miller, Sebastian (2014) An aggressive reduction scheme for the simple plant location problem. European Journal of Operational Research, 234 (3). pp. 674-682. ISSN 0377-2217

Galli, Laura and Letchford, Adam (2014) A compact variant of the QCR method for quadratically constrained quadratic 0-1 programs. Optimization Letters, 8 (4). pp. 1213-1224. ISSN 1862-4472

Burer, Samuel and Letchford, Adam (2014) Unbounded convex sets for non-convex mixed-integer quadratic programming. Mathematical Programming, 143 (1-2). pp. 231-256. ISSN 0025-5610

Djeumou Fomeni, Franklin and Letchford, Adam (2014) A dynamic programming heuristic for the quadratic knapsack problem. INFORMS Journal on Computing, 26 (1). pp. 173-182. ISSN 1526-5528

Aliev, Iskander and Letchford, Adam (2014) Iterated Chvatal-Gomory cuts and the geometry of numbers. SIAM Journal on Optimization, 24 (3). pp. 1294-1312. ISSN 1095-7189

Letchford, Adam and Nasiri, Saeideh D. (2014) Pricing routines for vehicle routing with time windows on road networks. Working Paper. The Department of Management Science, Lancaster University.

Amaral, André R. S. and Letchford, Adam (2013) A polyhedral approach to the single row facility layout problem. Mathematical Programming, 141 (1-2). pp. 453-477. ISSN 0025-5610

Letchford, Adam (2013) Computing upper bounds for the stable set problem using Lagrangian relaxation. In: LANCS International Workshop on Discrete and Nonlinear Optimisation, 2013-05-13 - 2013-05-15.

Letchford, Adam and Nasiri, Saeideh D. (2013) Compact formulations of the Steiner traveling salesman problem and related problems. European Journal of Operational Research, 228 (1). pp. 83-92. ISSN 0377-2217

Galli, Laura and Kaparis, Konstantinos and Letchford, Adam (2012) Gap inequalities for the max-cut problem: a cutting-plane algorithm. In: Combinatorial Optimization : Second International Symposium, ISCO 2012, Athens, Greece, April 19-21, 2012, Revised Selected Papers. Lecture Notes in Computer Science . Springer, Berlin, pp. 178-188. ISBN 9783642321467

Burer, S and Letchford, Adam (2012) Non-convex mixed-integer nonlinear programming : a survey. Surveys in Operations Research and Management Science, 17 (2). pp. 97-106. ISSN 1876-7354

Letchford, Adam (2012) Review of “Projecting systems of linear inequalities with binary variables”. Mathematical Reviews.

Letchford, Adam (2012) Review of “The Chvátal-Gomory closure of a strictly convex body”. Mathematical Reviews: MR2828758.

Letchford, Adam (2012) Review of “The Linear Ordering Problem: Exact and Heuristic Methods in Combinatorial Optimization”. Interfaces, 42 (3). pp. 324-325. ISSN 0092-2102

Letchford, Adam (2011) Review of “On the Chvátal rank of linear relaxations of the stable set polytope”. Mathematical Reviews.

Letchford, Adam (2011) Review of “On the dominant of the s-t cut polytope : vertices, facets and adjacency”. Mathematical Reviews.

Letchford, Adam (2011) Review of “Orbital branching”. Mathematical Reviews.

Caprara, Alberto and Letchford, Adam and Salazar Gonzalez, Juan Jose (2010) Lower bounds for the minimum linear arrangement of a graph. Electronic Notes in Discrete Mathematics, 36. pp. 843-849. ISSN 1571-0653

Kaparis, Konstantinos and Letchford, Adam (2010) Separation algorithms for 0-1 knapsack polytopes. Mathematical Programming, 124 (1-2). pp. 69-91. ISSN 0025-5610

Eglese, Richard and Letchford, Adam (2008) General routing problem. In: Encyclopedia of Optimization :. Springer, New York, pp. 1252-1254. ISBN 9780387747583

Clark, A and Eglese, Richard and Letchford, Adam and Wright, Mike (2008) Preface : Combinatorial optimization. Discrete Applied Mathematics, 156 (3). pp. 289-290. ISSN 0166-218X

Letchford, Adam (1999) On comb separation for the TSP. In: Oberwolfach Workshop on Combinatorial Optimisation, 1999-01-10 - 1999-01-16.