Professor Adam Letchford

Professor of Analytics and Optimisation

Research Overview

My research is in optimisation, i.e., finding the best solution to problems that have a huge (possibly infinite) number of solutions. Optimisation is an inter-disciplinary subject, lying at the interface between Operational Research, Computer Science, Applied Mathematics and Engineering. I concentrate mainly on methods for solving optimisation problems to proven optimality, rather than heuristic methods. I have a particular interest in combinatorial optimisation problems, i.e., problems in which variables are restricted to take integer (whole-number) values.

Selected Publications

Biperspective functions for mixed-integer fractional programs with indicator variables
Letchford, A., Ni, Q., Zhong, Z. 30/11/2021 In: Mathematical Programming. 190, 1-2, p. 39-55. 17 p.
Journal article

Facets from gadgets
Letchford, A., Vu, A. 1/01/2021 In: Mathematical Programming. 185, 1-2, p. 297-314. 18 p.
Journal article

A guide to conic optimisation and its applications
Letchford, A.N., Parkes, A.J. 22/11/2018 In: RAIRO Operations Research. 52, 4, p. 1087-1106. 20 p.
Journal article

On lifted cover inequalities: a new lifting procedure with unusual properties
Letchford, A.N., Souli, G. 17/01/2019 In: Operations Research Letters. 47, 2, p. 83-88. 6 p.
Journal article

Lifting the knapsack cover inequalities for the knapsack polytope
Letchford, A., Souli, G. 1/09/2020 In: Operations Research Letters. 48, 5, p. 607-611. 5 p.
Journal article

The capacitated vehicle routing problem: stronger bounds in pseudo-polynomial time
Letchford, A.N., Salazar Gonzalez, J.J. 1/01/2019 In: European Journal of Operational Research. 272, 1, p. 24–31. 8 p.
Journal article

A two-level graph partitioning problem arising in mobile wireless communications
Fairbrother, J., Letchford, A.N., Briggs, K. 04/2018 In: Computational Optimization and Applications. 69, 3, p. 653-676. 24 p.
Journal article

Newsvendor Problems
01/01/2020 → 31/12/2022
Research

STORi: Route optimisation for waste collection
01/10/2019 → 31/03/2023
Research

The 2013 Newton Institute Programme on Polynomial Optimisation
15/07/2013 → 09/08/2013
Other

Mixed-Integer Nonlinear Programming
01/10/2009 → …
Research

Fellowship: The Cut Polytope and Related Convex Bodies
01/08/2006 → 31/07/2011
Research

Algorithms for Vehicle Routing Problems
01/01/2003 → …
Research

Algorithms for the Travelling Salesman Problem
01/01/1999 → …
Research

Cutting-Plane Approaches to Integer Programming
01/01/1997 → …
Research

Integer Programming and Combinatorial Optimisation
01/01/1900 → …
Research

Improving a constructive heuristic for the general routing problem
Invited talk

2022 International Conference on Optimization and Decision Science
Participation in conference

4th Workshop on Arc Routing Problems
Participation in conference

2022 STOR-i Workshop on Prediction and Optimisation
Participation in conference

34th Conference of the European Chapter on Combinatorial Optimization
Participation in conference

3rd IMA/ORS Conference on the Mathematics of Operational Research
Participation in conference

34th Annual Conference of the Belgian Operational Research Society
Participation in conference

61st Annual Conference of the Operational Research Society
Participation in conference

30th European Conference on Operational Research
Participation in conference

2nd Joint IMA-ORS Conference
Participation in conference

60th Annual Conference of the Operational Research Society
Participation in conference

23rd International Symposium on Mathematical Programming
Participation in conference

23rd International Symposium on Mathematical Programming
Participation in conference

International Symposium on Combinatorial Optimization
Participation in conference

International Symposium on Combinatorial Optimization
Participation in conference

1st Joint IMA/ORS Conference
Participation in conference

Bit representations of mixed-integer quadratic programs
Invited talk

International Symposium on Combinatorial Optimisation
Participation in conference

International Symposium on Combinatorial Optimization
Participation in conference

International Symposium on Combinatorial Optimisation
Participation in conference

27th European Conference on Operational Research
Participation in conference

17th British-French-German Optimisation Conference (BFG 2015)
Participation in conference

An introduction to approximation algorithms (and inapproximability)
Invited talk

Mathematical Programming (Journal)
Editorial activity

Stronger multi-commodity flow formulations of the capacitated vehicle routing problem
Invited talk

Some unbounded convex sets arising in non-convex MIQP
Invited talk

Strengthening the reformulation-linearisation technique with cutting planes
Invited talk

Second order cone programming and its applications
Invited talk

25th European Conference on Operational Research (EURO XXV)
Participation in conference

21st International Symposium on Mathematical Programming
Participation in conference

Operations Research (Journal)
Editorial activity

EURO Journal on Computational Optimization (Journal)
Editorial activity

Applied Mathematical Optimization and Modelling
Participation in conference

International Symposium on Combinatorial Optimisation
Participation in conference

Reformulating mixed-integer quadratically-constrained quadratic programmes
Invited talk

Convex relaxations of the stable set problem
Invited talk

A tutorial on mixed-integer non-linear programming
Invited talk

Mixed-integer non-linear programming: a survey
Invited talk

Reformulation of 0-1 quadratically constrained quadratic programs
Invited talk

An introduction to second-order cone programming
Invited talk

London School of Economics
Visiting an external academic institution

Optimisation over cones
Invited talk

The Travelling Salesman Problem
Invited talk

European Chapter on Combinatorial Optimization
Participation in conference

Algorithmic Aspects in Information and Management
Participation in conference

Fifty years of cutting planes
Invited talk

On non-convex quadratic programming with box constraints
Invited talk

Recent progress on knapsack-based cutting planes
Invited talk

EURO XXIII - 23rd European Conference on Operational Research
Participation in conference

UK Operational Research Society Conference
Participation in conference

Discrete Optimization (Journal)
Editorial activity

International Network Optimization Conference
Participation in conference

Binary positive semidefinite matrices and some related polytopes
Invited talk

Discrete Applied Mathematics (Journal)
Editorial activity

Mathematical Programming Computation (Journal)
Editorial activity

International Symposium on Combinatorial Optimisation
Participation in conference

INFORMS Optimization Society
Participation in conference

ALIO/EURO Conference on Combinatorial Optimization
Participation in conference

An introduction to conic programming
Invited talk

Stronger upper bounds for the maximum stable set problem
Invited talk

Discrete Optimization (Journal)
Editorial activity

Semidefinite programming and combinatorial optimization
Invited talk

Algorithms for planar graphs
Invited talk

Vehicle routing games
Invited talk

Planar graphs and the traveling salesman problem
Invited talk

Solving discrete optimization problems by branch-and-cut
Invited talk

Vehicle routing games
Invited talk

11th International Conference on Integer Programming and Combinatorial Optimisation
Participation in conference

Mixed-Integer Programming Workshop
Participation in conference

Computational Optimization and Applications (Journal)
Editorial activity

Exploring the relationship between max-cut and stable set relaxations
Invited talk

The traveling salesman problem: inequalities and separation
Invited talk

The traveling salesman problem: inequalities and separation
Invited talk

Solving discrete optimization problems by branch-and-cut
Invited talk

International Symposium on Combinatorial Optimisation (CO2004)
Participation in conference

The traveling salesman problem: inequalities and separation
Invited talk

The traveling salesman problem: inequalities and separation
Invited talk

Solving discrete optimization problems by branch-and-cut
Invited talk

Solving discrete optimisation problems by branch-and-cut
Invited talk

On traveling salesman games
Invited talk

Mathematical Programming (Journal)
Editorial activity

Primal separation algorithms
Invited talk

Associazione Italiana di Ricerca Operativa (External organisation)
Member of an organisation

The Operational Research Society (External organisation)
Member of an organisation

Fellow of the Operational Research Society (FORS)
Fellowship awarded competitively

Recipient of IBM Faculty Award
Prize (including medals and awards)

Centre for Marketing Analytics & Forecasting

Centre for Transport & Logistics (CENTRAL), STOR-i Centre for Doctoral Training

  • Centre for Transport & Logistics (CENTRAL)
  • DSI - Foundations
  • Optimisation
  • STOR-i Centre for Doctoral Training