Let (W,S) be an irreducible
Weyl or affine Weyl group. In 1994, we constructed an algorithm for finding a
representative set of left cells (or an l.c.r. set for short) of W in a two-sided cell Ω.
Here, we introduce a new simpler algorithm for finding an l.c.r. set of W in Ω when
the subset F(Ω) of Ω is known. We introduce some technical tricks by some examples
for applying the algorithm and for finding the set F(Ω). The resulting set E(Ω) is
useful in verifying a conjecture of Lusztig that any left cell in an affine Weyl group is
left-connected.
Keywords
affine Weyl groups, left cells, two-sided cells, alcove
forms, algorithm