 
Summary: Trimming
Daryl Cooper and Darren D. Long
CONTENTS
1. Trimming
2. Some Examples
References
Both authors were supported in part by the NSF.
We consider the question of deciding whether or not certain
subgroups of certain cocompact Kleinian groups are geometri
cally finite or infinite. This is reduced to a question about sim
ilarity interval exchange maps. The concept of trimming pro
duces an practical algorithm to settle the latterquestion. This
algorithm has been implemented on a computer and the re
sults are perplexing.
In Cooper et al. 1997], we described an algo
rithm to determine whether a certain kind of sur
face in a threemanifold is quasifuchsian or a vir
tual bre. The surface in question is required to
be transverse to the suspension ow in a closed hy
perbolic threemanifold which bres, but need not
