  Turaev's shadow formula calculates the SU(2)-Reshetikhin-Turaev-Witten
invariants using shadows, and its expression is somehow similar to a Euler
characteristic. We give a short proof of this formula using skein theory.
  The formula applies to pairs (M,G) where M is a closed oriented 3-manifold
and GcM is a (possibly empty) colored framed trivalent graph (for instance, a
framed knot or link).
