Pseudosphere
Pseudosphere Pseu"do*sphere`, n. [Pseudo- + sphere.] (Geom.) The surface of constant negative curvature generated by the revolution of a tractrix. This surface corresponds in non-Euclidian space to the sphere in ordinary space. An important property of the surface is that any figure drawn upon it can be displaced in any way without tearing it or altering in size any of its elements. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

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• Pseudosphere — In geometry, a pseudosphere of radius R is a surface of curvature −1/ R 2 (precisely, a complete, simply connected surface of that curvature), by analogy with the sphere of radius R , which is a surface of curvature 1/ R 2. The term was… …   Wikipedia

• Pseudosphère — En géométrie, le terme de pseudosphère est utilisé pour décrire diverses surfaces dont la courbure de Gauss est constante et négative. Selon le contexte, il peut se référer soit à une surface théorique de courbure négative (une variété… …   Wikipédia en Français

• pseudosphere — pseudospherical /sooh deuh sfer i keuhl, sfear /, adj. /sooh deuh sfear /, n. Geom. a surface generated by revolving a tractrix about its asymptote. [1885 90; PSEUDO + SPHERE] * * * …   Universalium

• pseudosphere — noun A surface generated by rotating a tractrix about its asymptote See Also: pseudospherical …   Wiktionary

• pseudosphere — pseu·do·sphere …   English syllables

• pseudosphere — ˈsüdō+ˌ noun Etymology: International Scientific Vocabulary pseud + sphere: probably originally formed as Italian pseudosfera : a surface of constant negative curvature (as generated by the revolution of a tractrix about its axis) * * *… …   Useful english dictionary

• Logic and the philosophy of mathematics in the nineteenth century — John Stillwell INTRODUCTION In its history of over two thousand years, mathematics has seldom been disturbed by philosophical disputes. Ever since Plato, who is said to have put the slogan ‘Let no one who is not a geometer enter here’ over the… …   History of philosophy

• Tractrix — (from the Latin verb trahere pull, drag ), or tractrice, is the curve along which a small object moves, under the influence of friction, when pulled on a horizontal plane by a piece of thread and a puller that moves at a right angle to the… …   Wikipedia

• Differential geometry of surfaces — Carl Friedrich Gauss in 1828 In mathematics, the differential geometry of surfaces deals with smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives:… …   Wikipedia

• Demi-plan De Poincaré — Le demi plan de Poincaré est un sous ensemble des nombres complexes. Il a permis au mathématicien français Henri Poincaré d éclairer les travaux du Russe Nicolaï Lobatchevski. Sommaire 1 Le demi plan de Poincaré (1882) 1.1 Géométrie …   Wikipédia en Français