@article{Kroencke2016,
  author    = {Kr{\"o}ncke, Klaus},
  title     = {Rigidity and Infinitesimal Deformability of Ricci Solitons},
  series = {The journal of geometric analysis},
  volume    = {26},
  journal   = {The journal of geometric analysis},
  publisher = {Springer},
  address   = {New York},
  issn      = {1050-6926},
  doi       = {10.1007/s12220-015-9608-4},
  pages     = {1795 -- 1807},
  year      = {2016},
  abstract  = {In this paper, an obstruction against the integrability of certain infinitesimal solitonic deformations is given. Using this obstruction, we show that the complex projective spaces of even complex dimension are rigid as Ricci solitons although they have infinitesimal solitonic deformations.},
  language  = {en}
}
@unpublished{WenyiTianbo2005,
  author    = {Wenyi, Chen and Tianbo, Wang},
  title     = {The hypoellipticity of differential forms on closed manifolds},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29803},
  year      = {2005},
  abstract  = {In this paper we consider the hypo-ellipticity of differential forms on a closed manifold.The main results show that there are some topological obstruct for the existence of the differential forms with hypoellipticity.},
  language  = {de}
}