Regular patterns in Coxeter groups
Clicking on a chamber xC will exhibit all chambers yC with a link from y to x in the right W-graph.
G. Lusztig,
Nonlocal finiteness of a W-graph
, Representation Theory
1
(1996), pp. 25-30. Shows mu(pq
^{n}
, pq
^{m}
!= 0 for m > n > 0, m even, n odd.