Marine life of the Canary Islands a total of 5 different species of marine turtle that are sighted periodically in the islands, the most common of these being the loggerhead turtle. The other four are the green, hawksbill, leatherback, and Kemp's ridley turtle. Currently, there are no signs that any of these species breed in the islands, and so those seen in the water are usually migrating. However, it is believed that some of these species may have bred in the islands in the past, and there are records of several sightings of leatherback turtle on beaches in Fuerteventura, adding credibility to the theory. By far
History of manifolds and varieties History of manifolds and varieties The study of manifolds combines many important areas of mathematics: it generalizes concepts such as curves and surfaces as well as ideas from linear algebra and topology. Certain special classes of manifolds also have additional algebraic structure; they may behave like groups, for instance. In that case, they are called Lie Groups. Alternatively, they may be described by polynomial equations, in which case they are called algebraic varieties, and if they additionally carry a group structure, they are called algebraic groups. The term "manifold" comes from German "Mannigfaltigkeit," by Riemann. In English, "manifold" refers to