Professor Adam Letchford
Professor of Analytics and OptimisationResearch 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.
Web Links
Personal web page: www.lancs.ac.uk/staff/letchfoa
My Role
- Professor of Analytics and Optimisation
- Research Director, Department of Management Science
- Leading the "Foundations" Theme of the Data Science Institute
- Member of Executive Committee of the STOR-i CDT.
Current Teaching
- MSCI502: Introduction to Business Analytics and Operational Research
- MSCI534: Optimisation and Heuristics
- STOR608: "Sprint" on Stochastic and Robust Optimisation
External Roles
- Member of the REF2021 Mathematical Sciences Subpanel (since 2018)
- Member of the EPSRC Peer Review College (since 2006)
- Member of the UKRI Future Leaders Peer Review College (since 2018)
- Associate Editor of EURO Journal on Computational Optimization (since 2012)
- Associate Editor of the Open Journal on Mathematical Optimization (since 2018)
Qualifications
- BA (Hons) Linguistics & Psychology, Nottingham, 1989
- MSc Operational Research, Lancaster, 1993
- PhD Management Science, Lancaster, 1997
PhD Supervision Interests
I am looking for PhD students to work on exact solution algorithms for NP-hard optimisation problems. Candidates need to be comfortable with mathematics. Experience in programming (in, e.g., C, Julia, MatLab or Python) is highly desirable, as is basic knowledge of linear algebra and graph theory.
Selected Publications
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
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 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
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
New valid inequalities and facets for the simple plant location problem
Galli, L., Letchford, A.N., Miller, S. 16/09/2018 In: European Journal of Operational Research. 269, 3, p. 824-833. 10 p.
Journal article
An exact algorithm for a resource allocation problem in mobile wireless communications
Letchford, A.N., Ni, Q., Zhong, Z. 09/2017 In: Computational Optimization and Applications. 68, 2, p. 193-208. 16 p.
Journal article
Stronger multi-commodity flow formulations of the (capacitated) sequential ordering problem
Letchford, A., Salazar Gonzalez, J.J. 16/05/2016 In: European Journal of Operational Research. 251, 1, p. 74-84. 11 p.
Journal article
All Publications
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
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
Applied Mathematical Optimization and Modelling
Participation in conference
International Symposium on Combinatorial Optimisation
Participation in conference
EURO Journal on Computational Optimization (Journal)
Editorial activity
European Conference on Operational Research
Participation in conference
International Symposium on Mathematical Programming
Participation in conference
Operations Research (Journal)
Editorial activity
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
International Network Optimization Conference
Participation in conference
EURO XXIII - 23rd European Conference on Operational Research
Participation in conference
UK Operational Research Society Conference
Participation in conference
Discrete Optimization (Journal)
Editorial activity
Binary positive semidefinite matrices and some related polytopes
Invited talk
International Symposium on Combinatorial Optimisation
Participation in conference
INFORMS Optimization Society
Participation in conference
ALIO/EURO Conference on Combinatorial Optimization
Participation in conference
Discrete Applied Mathematics (Journal)
Editorial activity
Mathematical Programming Computation (Journal)
Editorial activity
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
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
The traveling salesman problem: inequalities and separation
Invited talk
Solving discrete optimization problems by branch-and-cut
Invited talk
The traveling salesman problem: inequalities and separation
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)
Optimisation
- Centre for Transport & Logistics (CENTRAL)
- DSI - Foundations
- Optimisation
- STOR-i Centre for Doctoral Training