By Lars Hörmander
Vol. I of Lars Hörmander's 4-volume treatise was once an exposition of the idea of distributions and Fourier research getting ready for the research of linear partial differential operators.
The current Vol. II is especially dedicated to operators with consistent coefficients. An research of the life and regularity of (fundamental) recommendations within the first chapters is by means of an intensive research of the Cauchy challenge. One bankruptcy is dedicated to the spectral idea of brief diversity perturbations of operators with consistent coefficients, and one other offers Fourier-Laplace representations of ideas of homogeneous differential equations with consistent coefficients. The final bankruptcy is a research of the heavily similar topic of convolution operators.