The comparisons on lines 2 vs. 4 and 6 and 7 vs. 9 and 11 clearly show that the quality of bisecting k-means whole-context clustering is comparable to, if not better than, Brown-type whole-context clustering.
keeping the representation constant in both cases (i.e., whole-context) enables us to see the algorithmic benefits of bisecting k-means as it appears to offer more useful clusters than those produced by the exchange algorithm.