View source for Exterior normal

''to a convex surface''

A vector perpendicular to a [[Supporting hyperplane|supporting hyperplane]] and directed towards that half-space defined by the supporting hyperplane which does not contain the points of the surface.



====Comments====
Analogously one defines the exterior normal to a body; for a survey in a wider context see [[#References|[a1]]].

====References====
<table><TR><TD valign="top">[a1]</TD> <TD valign="top">  R. Schneider,   "Boundary structure and curvature of convex bodies"  J. Tölke (ed.)  J.M. Wills (ed.) , ''Contributions to geometry'' , Birkhäuser  (1979)  pp. 13–59</TD></TR></table>