On closed curves whose spherical indicatrix of inner normals is centered
نویسندگان
چکیده
منابع مشابه
Isoperimetric Inequalities for Immersed Closed Spherical Curves
Let a: Sl ->S2 be a C2 immersion with length L and total curvature K . If a is regularly homotopic to a circle traversed once then L2 + K2 > 4n2 with equality if and only if a is a circle traversed once. If a has nonnegative geodesic curvature and multiple points then L + K > An with equality if and only if a is a great circle traversed twice.
متن کاملOn Varieties Whose Universal Cover Is a Product of Curves
We investigate a necessary condition for a compact complex manifold X of dimension n in order that its universal cover be the Cartesian product C of a curve C = Por H: the existence of a semispecial tensor ω. A semispecial tensor is a non zero section 0 6= ω ∈ H0(X,SnΩ1X(−KX)⊗ η)), where η is an invertible sheaf of 2-torsion (i.e., η ∼= OX). We show that this condition works out nicely, as a su...
متن کاملOn Closed Twisted Curves
Twisted curves in R' are those which have independent derivatives up to order m . For plane and spatial curves the twisted condition is equivalent to never vanishing curvature and torsion respectively. We give a necessary and sufficient condition for a (q, p)-curve on a torus to be twisted, and use those curves to construct closed twisted curves in R'" for all m .
متن کاملInterpolatory Subdivision Curves via Diffusion of Normals
In this paper, we propose a new interpolatory subdivision scheme for generating nice-looking curvature-continuous curves of round shapes. The scheme is based on a diffusion of normals. Given a subdivided polyline, the new polyline vertices inserted at the the splitting step are updated in order to fit diffused (averaged with appropriate weights) normals. Although the resulting interpolatory sub...
متن کاملCharacterization and axiomatization of all semigroups whose square is group
In this paper we give a characterization for all semigroups whose square is a group. Moreover, we axiomatize such semigroups and study some relations between the class of these semigroups and Grouplikes,introduced by the author. Also, we observe that this paper characterizes and axiomatizes a class of Homogroups (semigroups containing an ideal subgroup). Finally, several equivalent conditions ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Czechoslovak Mathematical Journal
سال: 1967
ISSN: 0011-4642,1572-9141
DOI: 10.21136/cmj.1967.100789