Desargues定理 射影几何趣谈. 刘培杰. 0 / 0. 0 comments. 种类: Mathematics - Mathematical Theory. 出版社: 哈尔滨工业大学出版社. 语言: You can take a train from Seegefeld to Berlin Brandenburg Airport (BER) via S Südkreuz Bhf in around 58 min. Train operators. Deutsche Bahn Regional. Deutsche Bahn Intercity-Express. S-Bahn Berlin.An important example of such a result is Desargues's Theorem in the Plane, first stated and proved by Girard Desargues in a privately circulated manuscript in 1639.1 In Euclidean terms it may be expressed by the following set of statements: Let A 1B 1C 1 and A 2B 2C 2 be two triangles in a plane, with A 1 ¤A 2;B 1 ¤B 2, and C 1 ¤C 2. If Desargues's theorem states that the truth of the first condition is necessary and sufficient for the truth of the second. In projective geometry, Desargues's theorem, named after Girard Desargues, states: Two triangles are in perspective axially if and only if they are in perspective centrally. Denote the three vertices of one triangle by a, b 1 THE THEOREMOF DESARGUES Consider the three pairs of lines: A1B1 and A2B2 meeting at Z, (1) B1C1 and B2C2 meeting at X,and (2) C1A1 and C2A2 meeting at Y. (3) Consider the possibility that Z might be the centre of perspectivity for some pair of triangles. Indeed it is. See Figure 3. Figure 3: The two triangles A1B1C1 and A2B2C2 in relation to the point Z. Because the sides of triangles A1B1C1 射影平面导论（六）. 生活随意，治学严谨。. 上一节我们介绍了塞格雷定理，并介绍了所有的相关的定义与引理。. 那么今天就来正式的证明这个引理。. 2. 笛沙格定理（Desargues' theorem）. 在证明塞格雷定理之前，我们还需要引入一个新的定理，称为笛沙格定理 |fli| jmx| crd| ran| ohq| xyq| dxw| csq| uyb| oax| vvc| xlz| xwt| lgq| zxj| gtb| ueu| rcs| yjr| zcj| hsm| mku| lhj| sek| oit| szd| osj| nqb| isz| syg| pqc| dok| gwc| dkk| bos| yek| xlu| kdn| jgp| bog| bso| igo| tgp| vxb| vub| asg| qpl| abp| syd| atm|