## Search

Now showing items 1-10 of 22

#### Replacing cliques by stars in quasi-media graphs

(University of Canterbury, 2002)

For a multi-set ∑ of splits (bipartitions) of a finite set X, we introduce the multi-split graph G(∑). This graph Is a natural extension of the Buneman graph. Indeed, it is shown that several results pertaining to the ...

#### Experimental and theoretical analysis of hybridization

(University of Canterbury, 2006)

We develop new heuristics and
an exact algorithm for calculating the
amount of hybridization between two
rooted binary phylogenetic trees. Calculating
the minimum number of hybridization
events is NP-hard, but essential ...

#### Tree representations of non-symmetric group-valued proximities

(University of Canterbury, 1999)

Let X be a finite set and let d be a function from X x X into an
arbitrary group Q. An example of such a function arises by taking a tree T
whose vertices include X, assigning two elements of Q to each edge of T ( one
for ...

#### A characterization for a set of partial partitions to define an X-tree

(University of Canterbury, 1999)

Trees whose vertices are partially labelled by elements of a finite
set X provide a natural way to represent partitions of subsets of X. The condition
under which a given collection of such partial partitions of X can ...

#### Reconstructing minimal rooted trees

(University of Canterbury, 1999)

For a set T of rooted binary leaf-labelled trees, we present an
algorithm that finds all of the minor-minimal trees that are compatible with
T. The running time of this algorithm is polynomial up to the number of trees
with ...

#### The structure of 3-connected matroids of path width three

(University of Canterbury, 2005)

A 3-connected matroid M is sequential or has path width 3 if its ground set E(M) has a sequential ordering, that is, an ordering (e₁, e₂, ... , ek) such that ({e₁,e₂, .. ,,ek}, {ek+₁,ek+₂, .. ,,en}) is a 3-separation for ...

#### Cyclic permutations and evolutionary trees

(University of Canterbury, 2002)

Given a tree T with leaf set X, there are certain ways of arranging
the elements of X in a circular order so that T can be embedded in the plane
and 'preserve' this ordering. We investigate some new combinatorial ...

#### On approximation of optimizing phylogenetic diversity for cluster systems

(University of Canterbury, 2009)

A basic question in conservation biology is how to maximize future
biodiversity as species face extinction. One way to approach this question
is by measuring the diversity of a set of species in terms of the evolutiona ...

#### Tree reconstruction via a closure operation on partial splits

(University of Canterbury, 1999)

A fundamental problem in biological classification is the reconstruction
of phylogenetic trees for a set X of species from a collection of either
subtrees or qualitative characters. This task is equivalent to tree ...

#### Fast computation of compatibility for phylogenies with nested taxa

(University of Canterbury, 2005)

Typically, supertree methods combine a collection of source trees in which just the leaves are labelled by taxa. In such methods the resulting supertree is also leaf-labelled. An underlying assumption in these methods is ...