positive root

If RE is a root systemMathworldPlanetmath, with E an Euclidean vector space, then a subset R+R is called a set of positive roots if there is a vector vE such that (α,v)>0 if αR+, and (α,v)<0 if αR\R+. http://planetmath.org/node/3645Roots which are not positive are called negative. Since -α is negative if and only if α is positive, exactly half the must be positive.

Title positive root
Canonical name PositiveRoot
Date of creation 2013-03-22 13:11:46
Last modified on 2013-03-22 13:11:46
Owner mathwizard (128)
Last modified by mathwizard (128)
Numerical id 8
Author mathwizard (128)
Entry type Definition
Classification msc 17B20
Defines negative root