Herdwick a "smit") of marking sheep for ownership. Before chemical dyes became available, this dye was made from either iron ore or graphite mixed with grease. For many years the legal method of identifying a particular shepherd's sheep were notches cut out of a sheep's ear, called "lug" marks—now replaced by ear tags. Herdwick The Herdwick is a breed of domestic sheep native to the Lake District of Cumbria in North West England. The name "Herdwick" is derived from the Old Norse "herdvyck", meaning sheep pasture. Though low in lambing capacity and perceived wool quality when compared to more common commercial
Ear decomposition smaller series-parallel graphs in one of two ways: series composition (identifying one terminal from one smaller graph with one terminal from the other smaller graph, and keeping the other two terminals as the terminals of the combined graph) and parallel composition (identifying both pairs of terminals from the two smaller graphs). The following result is due to : Moreover, any open ear decomposition of a 2-vertex-connected series-parallel graph must be nested. The result may be extended to series-parallel graphs that are not 2-vertex-connected by using open ear decompositions that start with a path between the two terminals. The concept of