Bramble

In British English, a "bramble" is any rough (usually wild) tangled prickly shrub—specifically the blackberry bush (Rubus fruticosus)—or any hybrid of similar appearance, with thorny stems. Bramble or brambleberry may also refer to the blackberry fruit or products of its fruit (e.g., bramble jelly). The shrub grows abundantly in all parts of the British Isles and harvesting the fruits in late summer and autumn is often considered a favourite pastime. It can also become a nuisance in gardens, sending down its strong suckering roots amongst hedges and shrubs.

Elsewhere, such as in the United States, the term "bramble" also refers to other members of the Rubus genus, which may or may not have prickly stems—notably the raspberry (Rubus idaeus) or its hybrids. The word comes from Germanic bram-bezi, whence come also German Brombeere, Dutch Braambes and French framboise.

Description

Bramble bushes have a distinctive growth form. They send up long, arching canes that do not flower or set fruit until the second year of growth. Brambles usually have trifoliate or palmately-compound leaves.

Bramble (surname)

Bramble is a surname. Notable people with the surname include:

Bramble (graph theory)

In graph theory, a bramble for an undirected graph G is a family of connected subgraphs of G that all touch each other: for every pair of disjoint subgraphs, there must exist an edge in G that has one endpoint in each subgraph. The order of a bramble is the smallest size of a hitting set, a set of vertices of G that has a nonempty intersection with each of the subgraphs. Brambles may be used to characterize the treewidth of G.

Treewidth and havens

A haven of order k in a graph G is a function β that maps each set X of fewer than k vertices to a connected component of G − X, in such a way that every two subsets β(X) and β(Y) touch each other. Thus, the set of images of β forms a bramble in G, with order k. Conversely, every bramble may be used to determine a haven: for each set X of size smaller than the order of the bramble, there is a unique connected component β(X) that contains all of the subgraphs in the bramble that are disjoint from X.

As Seymour and Thomas showed, the order of a bramble (or equivalently, of a haven) characterizes treewidth: a graph has a bramble of order k if and only if it has treewidth at least k − 1.