| Citation | His first important work was on the dual resonance model of scattering amplitudes. He was one of the authors of a classic paper on the quantum dynamics of a massless relativistic string. This was one of the first serious treatments of extended objects in relativistic quantum theory, and it introduced the light-cone guage. He has made essential contributions to the topological classification of solutions of field equations, in connection with both instantons and monopoles. He has done very significant work on infinite-dimensional Lie algebras and their applications to conformally invariant systems, with predictions for critical exponents in two-dimensional magnetic systems. |