natural metric
121Louisiana — This article is about the U.S. state of Louisiana. For other uses, see Louisiana (disambiguation). State of Louisiana État de Louisiane Léta de la Lwizyàn …
122Open set — Example: The points (x, y) satisfying x2 + y2 = r2 are colored blue. The points (x, y) satisfying x2 + y2 < r2 are colored red. The red points form an open set. The blue points form a closed set. The union of the red and blue points is a… …
123Riemann sphere — The Riemann sphere can be visualized as the complex number plane wrapped around a sphere (by some form of stereographic projection – details are given below). In mathematics, the Riemann sphere (or extended complex plane), named after the 19th… …
124Hydrogen economy — The hydrogen economy is a proposed system of delivering energy using hydrogen. The term hydrogen economy was coined by John Bockris during a talk he gave in 1970 at General Motors (GM) Technical Center.[1] Hydrogen advocates promote hydrogen as… …
125Sub-Riemannian manifold — In mathematics, a sub Riemannian manifold is a certain type of generalization of a Riemannian manifold. Roughly speaking, to measure distances in a sub Riemannian manifold,you are allowed to go only along curves tangent to so called horizontal… …
126Nordström's theory of gravitation — In theoretical physics, Nordström s theory of gravitation was a predecessor of general relativity. Strictly speaking, there were actually two distinct theories proposed by the Finnish theoretical physicist Gunnar Nordström, in 1912 and 1913… …
127History of the petroleum industry in Canada (frontier exploration and development) — discoveries took place near population centres or along lines of penetration into the frontier. The first oil play, for example, was in southern Ontario. The first western natural gas discovery occurred on a Canadian Pacific Railway right of way …
128Barbados — Barbadian /bahr bay dee euhn/, adj., n. /bahr bay dohz, dohs, deuhs/, n. an island in the E West Indies constituting an independent state in the Commonwealth of Nations: formerly a British colony. 257,731; 166 sq. mi. (430 sq. km). Cap.:… …
