On projective planes of order 20
On Projective Planes of Type (5, m).
On Rusakov’s -ary -groups
Properties of -ary groups connected with the affine geometry are considered. Some conditions for an -ary -group to be derived from a binary group are given. Necessary and sufficient conditions for an -ary group -derived from an additive group of a field to be an -group are obtained. The existence of non-commutative -ary -groups which are not derived from any group of arity for every , is proved.
On S. Gołąb's characterization of the anharmonic ratio
On the automorphism group of planes of Figueroa type
On the dimensions of automorphism groups of four-dimensional double loops.
On the fixed point of a collineation of the real projective plane.
On the geometry of field extensions.
On the geometry of symplectic involutions.
On the Group of Transformations of Constructible Euclidean Planes with Preserve a Single Distance.
On the incidence structures of polar spaces and quadrics.
On the planar translation structures
On Veldkamp lines.
One characterization of special translation planes
One configurational characterization of Ostrom nets
Bz the quadrileteral condition in a given net there is meant the following implication: If are arbitrary points, no three of them lie on the same line, with coll (collinearity) for any five from six couples then there follows the collinearity coll for the remaining couple . In the article there is proved the every net satisfying the preceding configuration condition is necessarity the Ostrom net (i.e., the net over a field). Conversely, every Ostrom net satisfies the above configuration...
One generalization of quasifield
One generalization of the fourth harmonic point (Preliminary communication)
Opérations sur les cartes et métamorphoses de la catégorie des G-ensembles.
We call metamorphosis of a given category an autoequivalence functor up to within natural equivalence. We show that, given a group G, the group of metamorphoses of the category of G-sets (as well as the corresponding group for ?sufficiently big? subcategories) may be naturally identified to the group of outer automorphism of G. We get by this way a natural description of a group of known operations on tessellations of a surface: the identity operation, the Poincaré duality, and four others which...
Orientierung in angeordneten affinen Räumen
Orthogonal, symplectic and unitary polar spaces sub-weakly embedded in projective space