In this work, using the Laplace invariants theory we give other proof for the following result: A proper Dupin hypersurfaces Mn for n ≥ 4 in Rn+1 with n distinct principal curvatures andconstant mobius curvature, cannot be parametrized by lines of curvature. Also, we study special classes of hypersurfaces Mn; n ≥ 3; in Rn+1, parametrized by lines of curvature with n distinct principal curvatures and we obtain a geometric relation when the Laplace invariants are vanish, we show that the foliations of Mn are umbilical hypersurfaces if and only if mijk = 0. Moreover, the foliations of Mn are Dupin hypersurfaces if and only if mij = 0.

In this work, using the Laplace invariants theory we give other proof for the following result: A proper Dupin hypersurfaces Mn for n ≥ 4 in Rn+1 with n distinct principal curvatures andconstant mobius curvature, cannot be parametrized by lines of curvature. Also, we study special classes of hypersurfaces Mn; n ≥ 3; in Rn+1, parametrized by lines of curvature with n distinct principal curvatures and we obtain a geometric relation when the Laplace invariants are vanish, we show that the foliations of Mn are umbilical hypersurfaces if and only if mijk = 0. Moreover, the foliations of Mn are Dupin hypersurfaces if and only if mij = 0.

In this paper we study hypersurfaces in R4 parametrized by lines of curvature with three distinct principal curvatures and with Laplace invariants mji = mki = 0; mjik 6= 0 for i; j; k distinct fixed indices. We characterize locally a generic family of such hypersurfaces in terms of the principal curvatures and three vector valued functions of one variable, this family includes a classe of Dupin hypersurfaces. Moreover, weshow that these vector valued functions are invariant under inversions and homotheties.

In this paper we study hypersurfaces in R4 parametrized by lines of curvature with three distinct principal curvatures and with Laplace invariants mji = mki = 0; mjik 6= 0 for i; j; k distinct fixed indices. We characterize locally a generic family of such hypersurfaces in terms of the principal curvatures and three vector valued functions of one variable, this family includes a classe of Dupin hypersurfaces. Moreover, weshow that these vector valued functions are invariant under inversions and homotheties.

In this work a sufficient condition is exhibited for a hypersurface in Rn+1 to be the envelope of a sphere congruence whose other envelope is contained in a unit sphere. A local parametrization for such envelopes is provided depending on an orthogonal local parametrization of Sn and their fundamental forms are described. Finally, a necessary and sufficient condition is presented so that such hypersurfaces are parametrized by lines of curvature and so that they are of rotation.

In this work a sufficient condition is exhibited for a hypersurface in Rn+1 to be the envelope of a sphere congruence whose other envelope is contained in a unit sphere. A local parametrization for such envelopes is provided depending on an orthogonal local parametrization of Sn and their fundamental forms are described. Finally, a necessary and sufficient condition is presented so that such hypersurfaces are parametrized by lines of curvature and so that they are of rotation.

En esta tesis se obtiene una clasificación casi completa de todos los productos tensoriales torcidos graduados de K [x ] con K [y ]. Para ello se usa una representación de un producto tensorial torcido graduado de K [x ] con K [y ] en el álgebra L(K N0 ), la cual está inmersa en el conjunto de matrices infinitas con entradas en K .De esta manera el problema de clasificar a los productos tensoriales torcidos graduados de K [x ] con K [y ] se traduce en el problema de clasificar a las matrices infinitas con entradas en K que satisfacen ciertas condiciones. Con este método se logra clasificar a los productos tensoriales graduados de K [x ] con K [y ] en un ejemplo particular y tres casos principales: álgebras cuadráticas, clasificadas porConner yGoetz por métodos diferentes, una familia llamada A(n,d ,a) con la propiedad de n +1 - extensión para cualquier n 2 y un tercer caso no co...

En esta tesis se obtiene una clasificación casi completa de todos los productos tensoriales torcidos graduados de K [x ] con K [y ]. Para ello se usa una representación de un producto tensorial torcido graduado de K [x ] con K [y ] en el álgebra L(K N0 ), la cual está inmersa en el conjunto de matrices infinitas con entradas en K .De esta manera el problema de clasificar a los productos tensoriales torcidos graduados de K [x ] con K [y ] se traduce en el problema de clasificar a las matrices infinitas con entradas en K que satisfacen ciertas condiciones. Con este método se logra clasificar a los productos tensoriales graduados de K [x ] con K [y ] en un ejemplo particular y tres casos principales: álgebras cuadráticas, clasificadas porConner yGoetz por métodos diferentes, una familia llamada A(n,d ,a) con la propiedad de n +1 - extensión para cualquier n 2 y un tercer caso no co...