Andreu Mas-Colell

Andreu Mas-Colell (; born 29 June 1944) is an economist, an expert in microeconomics and a prominent mathematical economist. Summarizing his and others' research in general equilibrium theory, his monograph gave a thorough exposition of research using differential topology. His textbook Microeconomic Theory, co-authored with Michael Whinston and Jerry Green, is the most used graduate microeconomics textbook in the world.

In June 2021, Spain’s Court of Auditors found that he was among those responsible for government expenditure on the unconstitutional 2017 Catalan independence referendum, and announced its intention to fine him millions of euros; one member of the court dissented, and an outcry from economists followed.

Biography A native of Barcelona , Mas-Colell completed his undergraduate studies at the University of Barcelona, earning a degree in economics in 1966. He moved to the University of Minnesota for his graduate studies, and completed his Ph.D. in 1972 under the supervision of Marcel Richter. He took a faculty position in mathematics and economics at the University of California, Berkeley, becoming a full professor in 1979. In 1981, he moved to Harvard University, and in 1988 he became the Louis Berkman Professor of Economics at Harvard. to attract top-notch scientists in all fields of knowledge, from philosophers to astrophysicists, to perform their research in 50 different host institutions in Catalonia. Mas-Colell served the Secretary General of the European Research Council from 2009 to 2010. In the 1960s and 1970s, however, Gérard Debreu and Stephen Smale led a revival of the use of differential calculus in mathematical economics. In particular, they were able to prove the existence of a general equilibrium, where earlier writers had failed, through the use of their novel mathematics: Baire category from general topology and Sard's lemma from differential topology and differential geometry. Their publications initiated a period of research "characterized by the use of elementary differential topology": "almost every area in economic theory where the differential approach has been pursued, including general equilibrium" was covered by Mas-Colell's monograph on differentiable analysis and economics.

Mas-Colell has also contributed to the theory of general equilibrium in topological vector lattices. The sets of prices and quantities can be described as partially ordered vector spaces, often as vector lattices. Economies with uncertain or dynamic decisions typically require that the vector spaces be infinite-dimensional, in which case the order properties of vector lattices allow stronger conclusions to be made. Recently researchers have studied nonlinear pricing: A "main motivation came from the fact that Mas-Colell's fundamental theory of welfare economics with no interiority assumptions crucially requires lattice properties of commodity spaces, even in finite-dimensional settings."

Books Mas-Colell is the author or co-author of:

The Theory of General Economic Equilibrium: a Differentiable Approach (Econometric Society Monographs in Pure Theory 9, Cambridge University Press, 1990, ). This book was evaluated for Mathematical Reviews by Dave Furth, who wrote that Mas-Colell's book is one of the first and still one of the most complete and most rigorous of the few textbooks on the applications of differential topology and global analysis to the theory of general economic equilibrium. .... People working in the field ought to own and to have used it already for some time. So those still wanting to consult for the first time and perhaps wanting to buy the book must be mathematicians interested in economic applications of the above-mentioned mathematical subjects. They will not regret consulting and/or buying it; the book is excellent. Microeconomic Theory (with Michael Dennis Whinston, Jerry R. Green, Oxford University Press, 1995, ). writes that this was "the most commonly used textbook in microeconomics", Jönköping excepted (the investigation covers all economics Ph.D. programs in Sweden for the academic year 2003-04). He is a recipient of the Creu de Sant Jordi, the highest civil honor of Catalonia, and of the King Juan Carlos Prize in Economics.

In 2025, Mas-Colell received the Alexandre Pedrós Award from the Societat Econòmica Barcelonesa d'Amics del País.