compact set with a boundary

  • 81Germany — /jerr meuh nee/, n. a republic in central Europe: after World War II divided into four zones, British, French, U.S., and Soviet, and in 1949 into East Germany and West Germany; East and West Germany were reunited in 1990. 84,068,216; 137,852 sq.… …

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  • 82Classification of manifolds — In mathematics, specifically geometry and topology, the classification of manifolds is a basic question, about which much is known, and many open questions remain. Contents 1 Main themes 1.1 Overview 1.2 Different categories and additional… …

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  • 83china — /chuy neuh/, n. 1. a translucent ceramic material, biscuit fired at a high temperature, its glaze fired at a low temperature. 2. any porcelain ware. 3. plates, cups, saucers, etc., collectively. 4. figurines made of porcelain or ceramic material …

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  • 84China — /chuy neuh/, n. 1. People s Republic of, a country in E Asia. 1,221,591,778; 3,691,502 sq. mi. (9,560,990 sq. km). Cap.: Beijing. 2. Republic of. Also called Nationalist China. a republic consisting mainly of the island of Taiwan off the SE coast …

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  • 85Black hole — For other uses, see Black hole (disambiguation). Simulated view of a black hole (center) in front of the Large Magellanic Cloud. Note the gravitat …

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  • 86Maximum likelihood — In statistics, maximum likelihood estimation (MLE) is a method of estimating the parameters of a statistical model. When applied to a data set and given a statistical model, maximum likelihood estimation provides estimates for the model s… …

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  • 87Topological manifold — In mathematics, a topological manifold is a Hausdorff topological space which looks locally like Euclidean space in a sense defined below. Topological manifolds form an important class of topological spaces with applications throughout… …

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  • 88History of Massachusetts — Flag of Massachusetts Massachusetts was first colonized by principally English Europeans in the early 17th century, and became the Commonwealth of Massachusetts in the 18th century. Prior to English colonization of the area, it was inhabited by a …

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  • 89Solution of the Poincaré conjecture — This entry describes the solution of the Poincaré conjecture at a level intended for the general public. The proof described is that of Grigori Perelman using the Ricci flow developed by Richard Hamilton. Links to other expositions for general… …

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  • 90ancient Rome — ▪ ancient state, Europe, Africa, and Asia Introduction       the state centred on the city of Rome. This article discusses the period from the founding of the city and the regal period, which began in 753 BC, through the events leading to the… …

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