On topological Tits buildings and their classification
On universal groups and three-manifolds.
On Veldkamp lines.
On volumes of arithmetic quotients of
We apply G. Prasad’s volume formula for the arithmetic quotients of semi-simple groups and Bruhat-Tits theory to study the covolumes of arithmetic subgroups of . As a result we prove that for any even dimension there exists a unique compact arithmetic hyperbolic -orbifold of the smallest volume. We give a formula for the Euler-Poincaré characteristic of the orbifolds and present an explicit description of their fundamental groups as the stabilizers of certain lattices in quadratic spaces. We...
On -distance in three dimensional space.
On -distance in -dimensional space.
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 planar partitions of Abelian groups
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...
Opravy k článku Afinity v třírozměrném afinním prostoru
Optimal four-dimensional codes over .
Optimierung konstant belegter Ovale und ein Hyperbel-Schnittsatz
Orbifold-Uniformizing Differential Equations. III. Arrangements Defined by 3-Dimensional Primitive Unitary Reflection Groups.
Ordinary differential equations and their exponentials
In the context of Synthetic Differential Geometry, we discuss vector fields/ordinary differential equations as actions; in particular, we exploit function space formation (exponential spaces) in the category of actions.
Ordnungsgeometrische Limessätze in kompakten Räumen. II. Mitteilung: Punktordnungswerte.
Orientation of absolute space .
Orientation of Absolute Space Sn