My research topics have been changing during my career.
- My first paper (1969) was devoted to uniform decay of solution of wave equation near non-trapping obstacles.
- My first large series of papers was devoted to Well-posedness of Cauchy Problem for non-Strictly Hyperbolic Equations.
- Then I switched to Propagation of Singularities.
- In 1979 after I proved Weyl conjecture my interests switched to Spectral Asymptotics (but Propagation of Singularities remains the crucial part of my work)
- After few years of detour to Asymptotics of the Ground State Energy for Heavy Atoms and Molecules (after I and M. Sigal justified Scott correction for molecules) - but Spectral Asymptotics were crucial there - I returned back to Spectral Asymptotics.
- Now I am working on my Monster size research monograph.