From The BBC News:
The £480,000 award is handed down by the Norwegian Academy of Science and Letters and supports a research field that is overlooked by the Nobel Prizes. The 79-year-old mathematician is based at the Courant Institute of Mathematical Sciences in New York, US. His work has provided new approaches to partial differential equations, which are used to describe non-linear systems such as the motion of gases. He constructed explicit solutions, identified classes of especially well-behaved systems, introduced an important notion of entropy, and, with US mathematician James Glimm, made a penetrating study of how solutions behave over a long period of time.
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