Deformation properties of one remarkable hypersurface by H. Takagi in ℝ4

Z. Dušek, O. Kowalski
2008 Mathematica Slovaca  
AbstractWe prove that the remarkable hypersurface found by H. Takagi in 1972 (as the first counter-example to the Nomizu conjecture on semi-symmetric spaces) is locally rigid.
doi:10.2478/s12175-008-0088-x fatcat:k67gh7mjlrfk5keofdd5552zc4