ICTP Prize Winner 1997

The ICTP Prize in the field of Mathematics (in honour of Ennio De Giorgi) has been awarded to Nitin Nitsure from the Tata Institute of Fundamental Research, Mumbai, India.

Nitin Nitsure has made highly significant contributions to moduli problems in algebraic geometry, which are internationally recognised.

He has calculated the Betti numbers of moduli spaces of parabolic bundles on a curve by generalising the gauge theoretic method of Atiyah and Bott and also by number theoretic methods using Weil zeta-functions. These results were used by other mathematicians in the study of Seifert 3-manifolds.

In an interesting paper he has studied the topology of a desingularisation of the moduli spaces of rank 2 bundles with trivial determinant on a curve.

In an important and well-known paper, he constructed the moduli spaces of Hitchin-pairs ("Higgs-bundles") on a curve as quasi-projective varieties and proved that the Hitchin map is proper. (Hitchin earlier constructed these spaces in the analytic category.) Nitsure's result was later generalised by Simpson to higher dimensions.

In a series of significant papers (one of them written in collaboration with C. Sabbah) he has developed during the last few years a subtle theory of moduli of regular holonomic D-modules and perverse sheaves. He constructs moduli spaces of these two kinds of objects and realises the Riemann-Hilbert correspondence as an analytic morphism between these moduli spaces.

Nitsure works on central problems in the area and his work is characterised by conceptual clarity, inventiveness and technical capacity of a high order.