natural one-to-one correspondence between Galois representations and some automorphic forms. The "naturalness" is guaranteed by the essential coincidence of L-functions. However, this condition is purely arithmetic and cannot be considered for a general one-dimensional function field in a straightforward way. Drinfeld pointed out that instead of automorphic forms one can consider automorphic perverse sheaves or automorphic D-modules. "Automorphicity" of these modules and the Langlands correspondence could be then understood in terms of the action of Hecke operators. Drinfeld has also worked in mathematical physics. In collaboration with his advisor Yuri Manin, he constructed the moduli space of Yang–Mills instantons, a result that was proved independently by Michael Atiyah and Nigel Hitchin. Drinfeld coined the term "quantum group" in reference to Hopf algebras that are deformations of simple Lie algebras, and connected them to the study of the Yang–Baxter equation, which is a necessary condition for the solvability of statistical mechanical models. He also generalized Hopf algebras to quasi-Hopf algebras and introduced the study of Drinfeld twists, which can be used to factorize the R-matrix corresponding to the solution of the Yang–Baxter equation associated with a quasitriangular Hopf algebra. Drinfeld has also collaborated with Alexander Beilinson to rebuild the theory of vertex algebras in a coordinate-free form, which have become increasingly important to two-dimensional conformal field theory, string theory, and the geometric Langlands program. Drinfeld and Beilinson published their work in 2004 in a book titled "Chiral Algebras." See also Drinfeld reciprocity Drinfeld upper half plane Manin–Drinfeld theorem Quantum group Chiral algebra Quasitriangular Hopf algebra Ruziewicz problem Notes References Victor Ginzburg, Preface to the special volume of Transformation Groups (vol 10, 3–4, December 2005, Birkhäuser) on occasion of Vladimir Drinfeld's 50th birthday, pp 277–278, Report by Manin External links Langlands Seminar homepage 1954 births 20th-century Ukrainian mathematicians 21st-century Ukrainian mathematicians Moscow State University alumni Fields Medalists Living people Algebraic geometers Number theorists Soviet mathematicians Ukrainian Jews Scientists from Kharkiv International Mathematical Olympiad participants University of Chicago faculty Institute for Advanced Study visiting scholars Members of the United States National Academy of Sciences