A characterization of certain 3-dimensional affino-projective spaces

A Characterization of the Hermitian Variety in Finite 3-Dimensional Projective Spaces

A combinatorial characterization of a non–singular Hermitian variety of the finite 3-dimensional projective space via its intersection numbers with respect to lines and planes is given.

A Characterization of Certain Conformally Euclidean Spaces of Class One

1. In this paper we will examine the metrics of conformally Euclidean spaces Cn (n^A) having the following two properties: (1) They are locally and isometrically imbeddable in Euclidean space of one higher dimension (£n+i), i.e. they are of class one. (2) With respect to a conformai coordinate system, the matrix of the second fundamental tensor [èy] has diagonal form. The condition for class on...

Projective embedding of projective spaces

In this paper, embeddings φ : M → P from a linear space (M,M) in a projective space (P,L) are studied. We give examples for dimM > dimP and show under which conditions equality holds. More precisely, we introduce properties (G) (for a line L ∈ L and for a plane E ⊂ M it holds that |L ∩ φ(M)| 6 = 1) and (E) (φ(E) = φ(E) ∩ φ(M), whereby φ(E) denotes the by φ(E) generated subspace of P ). If (G) a...

Secondary Steenrod Operations in Cohomology of Infinite-Dimensional Projective Spaces

The important role of the Steenrod operations Sq in the description of the cohomology of topological spaces, the calculation of various spectral sequences, and the study of homotopy properties of topological spaces and their continuous maps is well known [1, 2]. Projective spaces, in particular RP∞ and CP∞ , play a special role in the construction of Steenrod operations and their computation. I...

On the Projective Theory of Two Dimensional Riemann Spaces.