
 Symmetry In Physics Encyclopedia Article, Definition, History, Biography (Site not responding. Last check: 20071102) 
  an isometry of position is associated with an isometry of other vectors and pseudovectors, which is the linear part of the isometry of position, combined with an inversion of pseudovectors in the case that the isometry changes orientation. 
  In the case of mirror image symmetry in a plane with respect to scalars and vectors, the vectors at the plane are directed in the plane (or zero), and the associated pseudovectors are at the plane directed perpendicular to it (or zero). 
  In the case of mirror image symmetry in a plane with respect to scalars and vectors, and an axis of rotation perpendicular to the plane, the vectors at the point of intersection are zero, and the associated pseudovectors are along the axis. 
 www.merica.com /encyclopedia/Symmetry_in_physics (1054 words) 
