Calcul du rayon de la sphère inscrite dans le tétraèdre
Calibration of an ellipse's algebraic equation and direct determination of its parameters.
CAPS in Z(2,n)
We consider point sets in (Z^2,n) where no three points are on a line – also called caps or arcs. For the determination of caps with maximum cardinality and complete caps with minimum cardinality we provide integer linear programming formulations and identify some values for small n.
Caps on Hermitian varieties and maximal curves.
Catégorie des points d'un espace projectif
Catégories localement triviales. Catégories microtransitives
Categories of modules in synthetic differential geometry
Caustics in Greek antiquity
The word caustic was introduced by Tschirnhausen in 1686, in the Latin expression caustica curva. We show that the study of the optical caustics goes back well before, at least to the hellenistic period. We present a small Greek text, whose author is perhaps Geminus (1st cent. B.C.), describing an optical phenomenon called achilles. We show that the term achilles, which has appeared only once, to our knowledge, in the literature, means caustics by reflection. We complete the description of the achilles...
Central Automorphisms of Veblenian Nearaffine Planes
The paper deals with nearaffine planes described by H. A. Wilbrink. We consider their central automorphisms, i.e. automorphisms satisfying the Veblen condition, which become central collineations in connected projective planes. Moreover, a concept of central pseudo-automorphism is considered, i.e. some bijections in a nearaffine plane are not automorphisms but they become central collineations in the related projective planes.
Centrálne premietanie v ortogonálnom priestore
Certain comparative examinations of plane geometries according to Cayley-Klein.
Certain equalities and inequalities concerning polygons in .
Certain inequalities concerning bicentric quadrilaterals, hexagons and octagons.
Certain inequalities concerning some kinds of chordal polygons.
Ceva-Dreiecke.
Ceva's and Menelaus' theorems for the -dimensional space.
Cevians as sides of triangles.
Chain Spaces via Clifford Algebras.
Chamber systems, geometries and parabolic systems whose diagram contains only bonds of strength 1 and 2.
Characterization of diffeomorphisms that are symplectomorphisms
Let and be compact symplectic manifolds (resp. symplectic manifolds) of dimension 2n > 2. Fix 0 < s < n (resp. 0 < k ≤ n) and assume that a diffeomorphism Φ : X → Y maps all 2s-dimensional symplectic submanifolds of X to symplectic submanifolds of Y (resp. all isotropic k-dimensional tori of X to isotropic tori of Y). We prove that in both cases Φ is a conformal symplectomorphism, i.e., there is a constant c ≠0 such that .