  Here we present a new fixed parameter tractable algorithm to compute the
hybridization number r of two rooted binary phylogenetic trees on taxon set X
in time (6r)^r.poly(n), where n=|X|. The novelty of this approach is that it
avoids the use of Maximum Acyclic Agreement Forests (MAAFs) and instead
exploits the equivalence of the problem with a related problem from the
softwired clusters literature. This offers an alternative perspective on the
underlying combinatorial structure of the hybridization number problem.
