{"title":"Característica de Euler-Poincaré para poliedros 𝑛-tóricos","authors":"Luciene Arantes, W. Pedrochi, Rodrigo Martins","doi":"10.21711/2319023x2019/pmo717","DOIUrl":null,"url":null,"abstract":"The Euler-Poincaré Characteristic is a well-known topological invariant. The computation for compact surfaces depends on a highly refined topological tools, however in the case of convex polyhedra this invariant is constant equal to two and it follows, because convex polyhedra are homeomorphic to a sphere, from a simple verification of the formula which relates the number of vertices V, the number of edges A and the number of faces F of a polyhedron, more precisely, V − A + F = 2 (Euler’s Formula). In this work we present a proof, using only finite induction, for the computation this invariant taking into account, however, only a class of non-convex polyhedra, presented in a specific way, here called n-toric polyhedra, which are homeomorphic to an n-torus.","PeriodicalId":274953,"journal":{"name":"Revista Professor de Matemática On line","volume":"50 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Revista Professor de Matemática On line","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.21711/2319023x2019/pmo717","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The Euler-Poincaré Characteristic is a well-known topological invariant. The computation for compact surfaces depends on a highly refined topological tools, however in the case of convex polyhedra this invariant is constant equal to two and it follows, because convex polyhedra are homeomorphic to a sphere, from a simple verification of the formula which relates the number of vertices V, the number of edges A and the number of faces F of a polyhedron, more precisely, V − A + F = 2 (Euler’s Formula). In this work we present a proof, using only finite induction, for the computation this invariant taking into account, however, only a class of non-convex polyhedra, presented in a specific way, here called n-toric polyhedra, which are homeomorphic to an n-torus.
欧拉-庞卡罗特征是一个众所周知的拓扑不变量。紧致曲面的计算依赖于高度精细的拓扑工具,然而在凸多面体的情况下,这个不变量等于2,因为凸多面体与球体是同胚的,从一个简单的公式验证,它与多面体的顶点数V、边数a和面数F有关,更准确地说,V−a + F = 2(欧拉公式)。在这项工作中,我们只用有限归纳法证明了这个不变量的计算,然而,只有一类非凸多面体,以一种特定的方式呈现,这里称为n环面多面体,它们与n环面同胚。