[BioC] merging gene lists

[Rahul Kakkar M.D.]

if i have two lists of differentially regulated genes (they could be from 2 
different statistical tests, or differentially regulated genes in two treatment 
groups) which id like to compare, how would those with R/Bioconductor 
experience suggest i perform list comparisons to answer the following questions:

what is common between list 1 and 2?
what is in list 1 and not in 2?
what is in 2 but not 1?

your advice is greatly appreciated.

-- 
Rahul Kakkar M.D.
Postdoctoral Fellow
Elizabeth M. McNally Laboratory
Department of Medicine, Division of Cardiology
University of Chicago Hospitals
Chicago, IL USA