@unpublished{Baer2012,
  author    = {B{\"a}r, Christian},
  title     = {Some properties of solutions to weakly hypoelliptic equations},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-60064},
  year      = {2012},
  abstract  = {A linear differential operator L is called weakly hypoelliptic if any local solution u of Lu = 0 is smooth. We allow for systems, i.e. the coefficients may be matrices, not necessarily of square size. This is a huge class of important operators which covers all elliptic, overdetermined elliptic, subelliptic and parabolic equations. We extend several classical theorems from complex analysis to solutions of any weakly hypoelliptic equation: the Montel theorem providing convergent subsequences, the Vitali theorem ensuring convergence of a given sequence, and Riemann's first removable singularity theorem. In the case of constant coefficients we show that Liouville's theorem holds, any bounded solution must be constant and any L^p solution must vanish.},
  language  = {en}
}