  We give simple procedures to obtain the left and right keys of a
semi-standard Young tableau. Keys derive their interest from the fact that they
encode the characters of Demazure and opposite Demazure modules for the general
and special linear groups. Given the importance of keys, there are indeed
several procedures available in the literature to determine them. In
comparison, our procedures are new (to the best of our knowledge) and
especially simple. Having said that, we hasten to add that there is nothing new
in any individual ingredient that goes into our procedures. These ingredients
are all routine, straightforward, and (in any case) occur in the literature.
But they never quite seem to have been put together as done here.
  Our procedures end up repeatedly performing the Deodhar lifts, maximal lifts
for the left key and minimal lifts for right key. Together with the well known
fact that keys can be obtained by such repeated lifts, this justifies the
procedures. The relevance of Deodhar lifts to combinatorial models for Demazure
characters is well known in Standard Monomial Theory. Right and left keys
appear respectively as initial and final directions of Lakshmibai-Seshadri
paths in Littelmanns Path Model Theory.
