Boundary Value Problems for Linear PDEs with Variable Coefficients

A new method is introduced for studying boundary value problems for a class of linear PDEs with {\it variable} coefficients. This method is based on ideas recently introduced by the author for the study of boundary value problems for PDEs with {\it constant} coefficients. As illustrative examples the following boundary value problems are solved: (a) A Dirichlet and a Neumann problem on the half line for the time-dependent Schr\"odinger equation with a space dependent potential. (b) A Poincar\'e problem on the quarter plane for a variable coefficient eneralisation of the Laplace equation.