We extend a remarkable theorem of Derdziński and Shen, on the restrictions imposed on the Riemann tensor by the existence of a nontrivial Codazzi tensor. We show that the Codazzi equation can be replaced by a more general algebraic condition. The resulting extension applies both to the Riemann tensor and to generalized curvature tensors.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-1-1, author = {Carlo Alberto Mantica and Luca Guido Molinari}, title = {Extended Derdzi\'nski-Shen theorem for curvature tensors}, journal = {Colloquium Mathematicae}, volume = {126}, year = {2012}, pages = {1-6}, zbl = {1269.53018}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-1-1} }
Carlo Alberto Mantica; Luca Guido Molinari. Extended Derdziński-Shen theorem for curvature tensors. Colloquium Mathematicae, Tome 126 (2012) pp. 1-6. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm128-1-1/