Ailsa H. Land

June 1927

Brief Biography

Ailsa Land

Ailsa H. Land (née Dicken) was born in West Bromwich, Staffordshire, England but grew up close to Birmingham and Lichfield. With war becoming an imminent danger in 1939, Ailsa and her mother moved to Vancouver, Canada where she attended school. When World War II broke out, they traveled across the US to New York, and then subsequently back to Toronto to stay with the Dicken relatives. There Ailsa attended Malvern Collegiate Institute (younger by 18 months than others in class), based on her English school work.

In June 1943, Ailsa (now 16 but claimed to be 18) joined the Canadian Women’s Air Corps (CWAC), which her mother also joined. Almost two years later, both were able to return home to England to rejoin with Ailsa’s father, who was seriously ill.

Ailsa Land then turned her talents to pursuing an academic career, spent entirely at the London School of Economics (LSE). She entered the LSE as an undergraduate economics student in September 1946, and then progressed through the ranks of research assistant, lecturer, senior lecturer, reader, and then chaired professor. Her economics background and perspective informed her subsequent contributions to operations research, beginning with her 1956 dissertation on the application of OR techniques to the transportation of coking coal and extending to publications on a wide variety of applied problems (including international trade, manufacturing layout, machine scheduling, and sports analytics).

Ailsa is especially well known for her development, along with Alison Doig, of what came to be later called the branch-and-bound method for optimization problems with integer variables. Their groundbreaking 1960 work, published in Econometrica, has since been extensively cited and applied by the mathematical programming community. Indeed, most  serious implementations of OR optimization software include branch-and bound routines.  Interestingly, the work of Land and Doig was carried out at the LSE under the sponsorship of British Petroleum, in order to enhance existing linear programming models for refinery operations in which some variables were necessarily integral.

She also conducted early investigations of the traveling salesman problem, beginning with a 1955 paper with George Morton, and continuing with a 1979 research report on 100 city traveling salesman problems. This latter work applied cutting planes and a heuristic for subtour elimination constraints to obtain considerable improvement on previous approaches. In addition, Ailsa advanced OR methodology through publication of notable work on shortest path algorithms, quadratic programming, bicriteria decision problems, and statistical data fitting. Since retirement from the LSE in 1987, she has continued several research projects, resulting in contributions to data envelopment analysis, the quadratic assignment problem, and combinatorial auctions.

It is significant that Ailsa was not content with methodological contributions alone. She devoted much effort to the parallel development of computational tools for efficient solution of such problems. Indeed, she was on the forefront of computational OR, in which well-tested computer code is implemented, taking into account both theoretical considerations and efficient data structures. A significant work of this nature is the 1973 book Fortran Codes for Mathematical Programming: Linear, Quadratic and Discrete, written jointly with Susan Powell, which provided detailed documentation for computer implementations of optimization techniques as well as the underlying mathematical background and a suite of test problems. A subsequent 1979 publication, also with Susan Powell, offered guidance to consumers of mixed-integer programming and combinatorial programming. Her computer codes for data envelopment analysis and for the traveling salesman problem were all made freely available to the optimization community.

During Ailsa’s teaching career at the LSE, she helped to establish a two-year diploma in operational research at the LSE for students from the British Iron and Steel Association. Later she instituted a mathematical programming course at the undergraduate level as well as an advanced graduate course for the MSc program. She has the distinction of being the first woman professor of operational research in Britain, and at the LSE she mentored both master’s level and PhD students, several of whom have achieved international distinction.

Other Biographies

Wikipedia Entry for Ailsa Land 

Rosenhead J. & Williams P. Ailsa Land - A Profile.  LSE OR Newsletter May p. 12 (attached by permission of The Operational Research Society)


London School of Economics, BSc (1950), PhD (1956) Mathematics Genealogy 


Academic Affiliations

    London School of Economics 

Key Interests in OR/MS

Application Areas
  • Combinatorial Auctions
  • Data Envelopment Analysis
  • International Trade
  • Machine Scheduling 

Image Gallery and Slideshow

Memoirs and Autobiographies


Land, A (undated memoir) Professor Ailsa Land (link

Awards and Honors

Harold Larnder Prize, 1994 (link)

Selected Publications

Farbey, B. A., Land, A. H., & Murchland, J. D. (1967) The cascade algorithm for finding all shortest distances in a directed graph. Management Science, 14(1): 19–28.

Land, A. H. (1957) An application of linear programming to the transport of coking coal. Journal of the Royal Statistical Society, Series A, 120(3): 308–319.

Land, A. H. (1979) The solution of some 100-city symmetric travelling salesman problems. Research report, London School of Economics.

Land, A. H. & Doig, A. G. (1960) An automatic method of solving discrete programming problems. Econometrica, 28(3): 497–520.

Land, A. H. & Kuhn, H. W. (1959) Factor endowments and factor prices. Economica, 26(102): 137–144.

Land, A. H., Laporte, G., & Miliotis, P. (1978). A unified formulation of the machine scheduling problem. European Journal of Operational Research, 2(1): 32–35.

Land, A. H. & Morton, G. (1973) An inverse-basis method for Beale's quadratic programming algorithm. Management Science, 19(5): 510–516.

Land, A. H. & Powell, S. (1973) Fortran Codes for Mathematical Programming: Linear, Quadratic and Discrete. Wiley: New York.

Land, A. & Powell, S. (1979) Computer codes for problems of integer programming. Hammer, P. L., Johnson, E. J., & Korte, B. H., eds. Discrete Optimization II, Annals of Discrete Mathematics 5, 221–269.

Land, A.H., Powell, S., & Steinberg, R. (2006) PAUSE: A computationally tractable combinatorial auction. Cramton, P., Shoham, Y. & Steinberg, R., eds. Combinatorial Auctions, Chapter 6. MIT Press: Cambridge.

Land, A. H. & Stairs, S. W. (1967) The extension of the cascade algorithm to large graphs. Management Science, 14(1): 29–33.

Morton, G. & Land, A. H. (1955). A contribution to the “Travelling-Salesman Problem”. Journal of the Royal Statistical Society. Series B, 17(2): 185–203.

Additional Resources

The Ailsa Land Prize of the London School of Economics (link