|Francisco Santos (b. 1968) is a full professor at the University of Cantabria and has held visiting positions in UC Davis, École Normale Supérieure de Paris, Freie Universität Berlin (where he currently holds an Einstein Visiting Fellowship for the period 2016-2019) and MSRI Berkeley, where he was a Research Professor in the fall of 2003 and is now a Clay Senior Scholar.
Santos research has always centered on geometric combinatorics. Soon after finishing his Ph D (1995) he did extensive work on oriented matroids  and spaces of triangulations of polytopes and point configurations . This led for example to the first examples of point sets with a non-connected graph of triangulations and to his invitation as Section Speaker in the International Congress of Mathematicians of Madrid 2006 .
His most celebrated result is the disproof of the notorious “Hirsch conjecture”, which had arisen in linear optimization theory in 1957 and became famous as a central problem in combinatorial optimization and in the theory of polyhedra in the decades after that. Santos’ paper describing the counter-example  was awarded the Fulkerson Prize in 2015. This is a prize awarded jointly by the American Mathematical Society and the Society for Mathematoical Optimization for the best mathematical research paper in Discrete Mathematics in the previous three years.
Santos is married and has two children, aged 18 and 14.