Leatherback Trust conservation initiatives throughout Costa Rica and around the world. The Leatherback Trust currently supports conservation projects for the leatherback, green and olive ridley sea turtles in Costa Rica; leatherback and loggerhead sea turtles in South Africa; loggerhead sea turtles in Greece; and hawksbill sea turtles in the US Virgin Islands. Las Baulas National Marine Park was formed by a Presidential decree in 1991 and officially confirmed by law in 1995. Prior to the creation of the park almost 100% of all the sea turtles eggs laid in the region were collected illegally (poaching), but now this has been effectively ended.
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