Gopal Prasad (born 31 July 1945 in Ghazipur, India) is an Indian-American mathematician.

There he began a long and extensive collaboration with his advisor M. S. Raghunathan on several topics including the study of lattices in semi-simple Lie groups and the congruence subgroup problem.

In 1992 he left TIFR to join the faculty at the University of Michigan in Ann Arbor, where he is the Raoul Bott Professor Emeritus of Mathematics.

Prasad's early work was on discrete subgroups of real and p-adic semi-simple groups.

He proved the "strong approximation" property for simply connected semi-simple groups over global function fields [3].

Later, together with Andrei Rapinchuk, Prasad gave a precise computation of the metaplectic kernel for all simply connected semi-simple groups, see [14].

Using this formula and certain number theoretic and Galois-cohomological estimates, Armand Borel and Gopal Prasad proved several finiteness theorems about arithmetic groups, [6].

The volume formula, together with number-theoretic and Bruhat-Tits theoretic considerations led to a classification, by Gopal Prasad and Sai-Kee Yeung, of fake projective planes (in the theory of smooth projective complex surfaces) into 28 non-empty classes [21] (see also [22] and [23]).

This classification, together with computations by Donald Cartwright and Tim Steger, has led to a complete list of fake projective planes.

Prasad has worked on the representation theory of reductive p-adic groups with Allen Moy.

The results and techniques introduced in these two papers [8],[9] enabled a series of important developments in the field.

In another joint work, that has been used in the geometric Langlands program, Prasad and Yu determined all the quasi-reductive group schemes over a discrete valuation ring (DVR), [25].

In collaboration with Brian Conrad and Ofer Gabber, Prasad has studied the structure of pseudo-reductive groups, and also provided proofs of the conjugacy theorems for general smooth connected linear algebraic groups, announced without detailed proofs by Armand Borel and Jacques Tits; their research monograph [26] contains all this.

There was a Bourbaki seminar in March 2010 on the work of Tits, Conrad-Gabber-Prasad on pseudo-reductive groups.

Prasad has developed new methods for unramified and tamely ramified descents in Bruhat-Tits theory [28][29].

Together with Tasho Kaletha, he has recently written a book [30] on Bruhat-Tits theory which contains new proofs of several results.

Prasad has received the Guggenheim Fellowship, the Humboldt Senior Research Award, and the Raoul Bott Professorship at the University of Michigan.

He was awarded the Shanti Swarup Bhatnagar prize (by the Council of Scientific and Industrial Research of the Government of India).

Prasad gave an invited talk in the International Congress of Mathematicians held in Kyoto in 1990.

Finiteness theorems for discrete subgroups of bounded covolume in semi-simple groups, Publ.Math.IHES 69(1989), 119–171; Addendum: ibid, 71(1990); with A.Borel.

Topological central extensions of semi-simple groups over local fields, Annals of Mathematics 119(1984), 143–268; with M.S.Raghunathan.

On the fields generated by the lengths of closed geodesics in locally symmetric spaces, preprint; with A.S.Rapinchuk.

Nonexistence of arithmetic fake compact hermitian symmetric spaces of type other than A_n, n<5, J.Math.Soc.Japan; with Sai-Kee Yeung.

Pseudo-reductive groups, second edition, New Mathematical Monographs #26, xxiv+665 pages, Cambridge University Press, 2015; with Brian Conrad and Ofer Gabber.

Classification of Pseudo-reductive groups, Annals of Mathematics Studies #191, 245 pages, Princeton University Press, 2015; with Brian Conrad.

Bruhat--Tits theory: a new approach, Cambridge University Press, UK, 2022; with Tasho Kaletha.