Descartes园定理的非欧推广
An Extension of Descartes Circle Theorem in Non-Euclidean Spaces
-
摘要: 本文证明:如果在曲率为K的n维常曲率空间中n+2个球两两外切,用k1,k2……kn+2表示它们的主曲率,则下列关系成立:
(???19880202???ki)2-n???19880202???ki2=2nK
当K=0,n=2时,即得Descartes园定理的原始形式。Abstract: In this paper we have proved that if n+2 spheres in n-dimensional spaces with constant curvature K touch each other externally and if k1,k2,……kn+2 denote their principle curvatures, then the following relationhold.
(???19880202???ki)2-n???19880202???ki2=2nK
When K=0 and n=2, We get the original form of Descartes circle theorem.