On conformally recurrent Ricci-recurrent manifolds
It was conjectured in [26] that, for all submanifolds of all real space forms , the Wintgen inequality is valid at all points of , whereby is the normalised scalar curvature of the Riemannian manifold and , respectively , are the squared mean curvature and the normalised scalar normal curvature of the submanifold in the ambient space , and this conjecture was shown there to be true whenever codimension . For a given Riemannian manifold , this inequality can be interpreted as follows:...
We classify locally the induced Riemannian metrics of all irreducible double-ruled hypersurfaces in .
We develop an algebraic version of Cartan’s method of equivalence or an analog of Tanaka prolongation for the (extrinsic) geometry of curves of flags of a vector space W with respect to the action of a subgroup G of GL(W). Under some natural assumptions on the subgroup G and on the flags, one can pass from the filtered objects to the corresponding graded objects and describe the construction of canonical bundles of moving frames for these curves in the language of pure linear algebra. The scope...