Reproducing kernels and potential theory for the Bergman spaces
The role of weighted biharmonic Green functions in weighted Bergman spaces was first studied in the beginning of the 50's by Paul Garabedian. In 1951 he showed that they are closely related to reproducing kernel functions of weighted Bergman spaces. Half a century later, the properties of biharmonic functions turned out to be crucial to the factorization theory of Bergman spaces on the unit disk.