翻訳と辞書
Words near each other
・ Desmia stenoleuca
・ Desmia strigivitralis
・ Desmia subdivisalis
・ Desmia tages
・ Desmia tellesalis
・ Desmia tenuimaculata
・ Desmia tenuizona
・ Desmia tetratocera
・ Desmia trimaculalis
・ Desmia ufeus
・ Desmia unipunctalis
・ Desmia validalis
・ Desmia vicina
・ Desmia vulcanalis
・ Desmia zebinalis
Desmic system
・ Desmichels Treaty
・ Desmidiaceae
・ Desmidiales
・ Desmidium
・ Desmidophorus
・ Desmidophorus cumingi
・ Desmin
・ Desmin-related myofibrillar myopathy
・ Desminocnemis
・ Desminocnemis hypochryseis
・ Desminocnemis platyleuca
・ Desminocnemis prittwitzi
・ Desmiphora
・ Desmiphora aegrota


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Desmic system : ウィキペディア英語版
Desmic system

In projective geometry, a desmic system is a set of three tetrahedra in 3-dimensional projective space, such that any two are desmic, (i.e. related such that each edge of one cuts a pair of opposite edges of the other). It was introduced by . The three tetrahedra of a desmic system are contained in a pencil of quartic surfaces. The name "desmic" comes from the Greek word δεσμός, meaning band or chain, referring to the pencil of quartics.
Every line that passes through two vertices of two tetrahedra in the system also passes through a vertex of the third tetrahedron.
The 12 vertices of the desmic system and the 16 lines formed in this way are the points and lines of a Reye configuration.
==Example==
The three tetrahedra given by the equations
*\displaystyle (w^2-x^2)(y^2-z^2) = 0
*\displaystyle (w^2-y^2)(x^2-z^2) = 0
*\displaystyle (w^2-z^2)(y^2-x^2) = 0
form a desmic system, contained in the pencil of quartics
*\displaystyle a(w^2x^2+y^2z^2) + b(w^2y^2+x^2z^2) + c (w^2z^2+x^2y^2) = 0
for ''a'' + ''b'' + ''c'' = 0.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Desmic system」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.