He did win the Von Neumann award in 1978 and was awarded the Leroy
P. Steele Prize by the AMS. These are not the Fields Medal, true,
but they are math awards.
http://www.nobel.se/economics/laureates/1994/nash-autobio.html
the theory of noncooperative games.
prevailing trend among mathematicians for many years was to search
for "elementary" (i.e., algebraic) proofs and extensions of that
result, and, indeed, to treat all of game theory as little more
than a branch of the theory of linear inequalities, which was then
in an exciting period of rapid growth. John Nash, however, adopted
a radically different viewpoint. As a young graduate student at
Princeton, he conceived the idea of noncooperative equilibrium in
multi-person games and went on to prove a general existence theorem
for this solution concept. His proofs (1950, 1951) are beautiful
applications of the topological fixed point theorems of Brouwer and
Kakutani. Indeed, their present-day familiarity among economists
and others can be traced back to Nash's work, since that work was
the acknowledged basis for the seminal papers of Debreu and Arrow
(1952, 1954) on general equilibrium that touched off the remarkable
revitalization and mathematical deepening that transformed economic
theory in the 1950's and 1960's. This revolution was undoubtedly
going to occur in any case, but in the actual train of events a
most decisive role was played by Nash's clear penetration into the
heart of a fundamental process of social interaction.
"Nash's equilibrium proofs were non-constructive, and for many years
it seemed that the nonlinearity of the problem would prevent the
actual numerical solution of any but the simplest noncooperative
games. The breakthrough came in 1964 with an ingenious algorithm
for the bimatrix case (i.e., finite, two-player games) devised by
Carlton Lemke and J. T. Howson, Jr. It provided both a constructive
existence proof and a practical means of calculation.
"The underlying logic, involving motions on the edges of an
appropriate polyhedron, was simple and elegant yet conceptually
daring in an epoch when such motions were typically contemplated in
the context of linear programming. Lemke took the lead in
exploiting the many ramifications and applications of this
procedure, which range from the very basic linear complementarity
problem of mathematical programming to the problem of calculating
fixed points of continuous, nonlinear mappings arising in various
contexts. A new chapter in the theory and practice of mathematical
programming was thereby opened which quickly became a very active
and well-populated area of research. Nor was the game-theory aspect
neglected: the path-following methodology has been a source of many
new insights into the nature of the Nash Equilibria."
So not only was his other mathematical work recognized by the
mathematical community, the work that would eventually lead to his
Memorial Nobel Prize in Economics was also recognized by the
mathematical community ->before<- it was awarded the Memorial Nobel.
