Total Absolute Curvature:
Given a mapping f of a surface
M into space, the total absolute curvature is

where K is the Gaussian curvature. It can be shown
that the total absolute curvature is always at least 4 - X(M)
where X(M) represents the
Euler characteristic of
M. When equality holds, the mapping is called
tight.
8/12/94 dpvc@geom.umn.edu --
The Geometry Center