Infinite Dimensional Families of Locally Nonsolvable Partial Differential Operators

Michael Christ, G. E. Karadzhov
1996 Mathematical Research Letters  
Local solvability is analyzed for natural families of partial differential operators having double characteristics. In some families the set of all operators that are not locally solvable is shown to have both infinite dimension and infinite codimension.
doi:10.4310/mrl.1996.v3.n4.a9 fatcat:cbxgg3blobcslgbesjdthk3atu