Isotropic affine hypersurfaces of dimension 5 (Q483036)

The authors prove the following theorem and obtain in particular a complete classification of isotropic affine hypersurfaces in dimension 5: Theorem. Let \(M^n\) be a positive definite affine hypersurface with isotropic difference tensor in \(\mathbb R^{n+1}\). Assume that \(n>2\) and \(M\) is not congruent to a quadric. Then either \(n=5\), \(n=8\), \(n=14\) or \(n=26\).