Cornell University
Library
Cornell UniversityLibrary

eCommons

Help
Log In(current)
  1. Home
  2. Cornell Computing and Information Science
  3. Computer Science
  4. Computer Science Technical Reports
  5. On Branching Numbers of Normal Manifolds

On Branching Numbers of Normal Manifolds

File(s)
92-1283.pdf (1.18 MB)
92-1283.ps (257.51 KB)
Permanent Link(s)
https://hdl.handle.net/1813/7123
Collections
Computer Science Technical Reports
Author
Ralph, Daniel
Abstract

Let $\cal M$ be a finite piecewise linear (pl) manifold of $IR^n$, and $P$ : $IR^n \rightarrow IR^n$ be pl with respect to $\cal M$, i.e. $P$ is affine on each set in $\cal M$. The branching number of $\cal M$, Kuhn and Lowen [8], is the maximum number of sets in $\cal M$ that can contain any common face of codimension 2. [8, Thm. 5.3] shows that if $\cal M$ has branching number less than or equal to 4, then $P$ is a homeomorphism if and only if it is coherently oriented, i.e. the determinants of $P$ on the sets in $\cal M$ have the same nonzero sign. Let $C$ be a nonempty polyhedral convex set in $IR^n$, and $A \in IR^{nxn}$. Robinson [14] defines a finite pl manifold $\cal N_C$ of $IR^n$ called the normal manifold of $C$; and the normal map $A_C$ : $IR^n \rightarrow IR^n$ induced by ($A, C$), which is pl with respect to $\cal N_C$. [14, Thm. 4.3] shows that $A_C$ is homeomorphic if and only if it is coherently oriented. We show that $\cal N_C$ has branching number less than or equal to 4, hence Robinson's result is actually a corollary of Kuhn and Lowen's. Key Words: Piecewise linear, piecewise affine, branching number, normal map, pl-normal, normal manifold, homeomorphism, coherently oriented.

Date Issued
1992-05
Publisher
Cornell University
Keywords
computer science
•
technical report
Previously Published as
http://techreports.library.cornell.edu:8081/Dienst/UI/1.0/Display/cul.cs/TR92-1283
Type
technical report

Site Statistics | Help

About eCommons | Policies | Terms of use | Contact Us

copyright © 2002-2026 Cornell University Library | Privacy | Web Accessibility Assistance