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Thomsen's Theorem
Thomsen's theorem, named after Gerhard Thomsen, is a theorem in elementary geometry. It shows that a certain path constructed by line segments being parallel to the edges of a triangle always ends up at its starting point. Consider an arbitrary triangle ''ABC'' with a point ''P''1 on its edge ''BC''. A sequence of points and parallel lines is constructed as follows. The parallel line to ''AC'' through ''P''1 intersects ''AB'' in ''P''2 and the parallel line to BC through ''P''2 intersects AC in ''P''3. Continuing in this fashion the parallel line to AB through ''P''3 intersects BC in ''P''4 and the parallel line to ''AC'' through ''P''4 intersects ''AB'' in ''P''5. Finally the parallel line to ''BC'' through ''P''5 intersects AC in ''P''6 and the parallel line to ''AB'' through ''P''6 intersects ''BC'' in ''P''7. Thomsen's theorem now states that ''P''7 is identical to ''P''1 and hence the construction always leads to a closed path ''P''1''P''2''P''3''P''4''P''5''P''6''P''1 Ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satz Von Thomsen
' (German for ''sentence'', ''movement'', ''set'', ''setting'') is any single member of a musical piece, which in and of itself displays a complete sense, (Hugo Riemann, Riemann 1976: 841) such as a sentence (music), sentence, phrase (music), phrase, or movement (music), movement. Notes Sources *Riemann (1976). Cited in Jean-Jacques Nattiez, Nattiez, Jean-Jacques (1990). ''Music and Discourse: Toward a Semiology of Music'' (''Musicologie générale et sémiologue'', 1987). Translated by Carolyn Abbate (1990). . Formal sections in music analysis German words and phrases {{music-theory-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerhard Thomsen
Gerhard Thomsen (23 June 1899 – 4 January 1934) was a German mathematician, probably best known for his work in various branches of geometry. Life Thomsen was born on 23 June 1899 in Hamburg. His father, Georg Thomsen, was a physician. Thomsen grew up in Hamburg and attended the Johanneum ( gymnasium/highschool) from 1908 to 1917. After completing school he served in the army during the last year of World War I. In 1919 he became of the first students at the newly founded University of Hamburg majoring in mathematics and natural science. Aside from a temporary interlude Thomsen studied in Hamburg until 1923. He received a certification to teach at highschools the fall of 1922 and finally his PhD in the summer of the following year. After he worked shortly as an assistant at the Karlsruhe Institute of Technology before returning to Hamburg in a similar capacity in the spring of 1925. While working on his habilitation thesis Thomsen spend one year in Rome on Rockefeller grant to st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygonal Chain
In geometry, a polygonal chain is a connected series of line segments. More formally, a polygonal chain is a curve specified by a sequence of points (A_1, A_2, \dots, A_n) called its vertices. The curve itself consists of the line segments connecting the consecutive vertices. Name A polygonal chain may also be called a polygonal curve, polygonal path, polyline,. piecewise linear curve, broken line or, in geographic information systems, a linestring or linear ring. Variations A simple polygonal chain is one in which only consecutive (or the first and the last) segments intersect and only at their endpoints. A closed polygonal chain is one in which the first vertex coincides with the last one, or, alternatively, the first and the last vertices are also connected by a line segment. A simple closed polygonal chain in the plane is the boundary of a simple polygon. Often the term "polygon" is used in the meaning of "closed polygonal chain", but in some cases it is important to dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangle
A triangle is a polygon with three Edge (geometry), edges and three Vertex (geometry), vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, any three points, when non-Collinearity, collinear, determine a unique triangle and simultaneously, a unique Plane (mathematics), plane (i.e. a two-dimensional Euclidean space). In other words, there is only one plane that contains that triangle, and every triangle is contained in some plane. If the entire geometry is only the Euclidean plane, there is only one plane and all triangles are contained in it; however, in higher-dimensional Euclidean spaces, this is no longer true. This article is about triangles in Euclidean geometry, and in particular, the Euclidean plane, except where otherwise noted. Types of triangle The terminology for categorizing triangles is more than two thousand years old, having been defined on the very first page of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point (geometry)
In classical Euclidean geometry, a point is a primitive notion that models an exact location in space, and has no length, width, or thickness. In modern mathematics, a point refers more generally to an element of some set called a space. Being a primitive notion means that a point cannot be defined in terms of previously defined objects. That is, a point is defined only by some properties, called axioms, that it must satisfy; for example, ''"there is exactly one line that passes through two different points"''. Points in Euclidean geometry Points, considered within the framework of Euclidean geometry, are one of the most fundamental objects. Euclid originally defined the point as "that which has no part". In two-dimensional Euclidean space, a point is represented by an ordered pair (, ) of numbers, where the first number conventionally represents the horizontal and is often denoted by , and the second number conventionally represents the vertical and is often denoted by . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallel Lines
In geometry, parallel lines are coplanar straight lines that do not intersect at any point. Parallel planes are planes in the same three-dimensional space that never meet. ''Parallel curves'' are curves that do not touch each other or intersect and keep a fixed minimum distance. In three-dimensional Euclidean space, a line and a plane that do not share a point are also said to be parallel. However, two noncoplanar lines are called ''skew lines''. Parallel lines are the subject of Euclid's parallel postulate. Parallelism is primarily a property of affine geometries and Euclidean geometry is a special instance of this type of geometry. In some other geometries, such as hyperbolic geometry, lines can have analogous properties that are referred to as parallelism. Symbol The parallel symbol is \parallel. For example, AB \parallel CD indicates that line ''AB'' is parallel to line ''CD''. In the Unicode character set, the "parallel" and "not parallel" signs have codepoint ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intersection (Euclidean Geometry)
In geometry, an intersection is a point, line, or curve common to two or more objects (such as lines, curves, planes, and surfaces). The simplest case in Euclidean geometry is the line–line intersection between two distinct line (geometry), lines, which either is one point (geometry), point or does not exist (if the lines are parallel lines, parallel). Other types of geometric intersection include: * Line–plane intersection * Line–sphere intersection * Intersection of a polyhedron with a line * Line segment intersection * Intersection curve Determination of the intersection of flat (geometry), flats – linear geometric objects embedded in a higher-dimensional space – is a simple task of linear algebra, namely the solution of a system of linear equations. In general the determination of an intersection leads to non-linear equations, which can be numerical solution, solved numerically, for example using Newton iteration. Intersection problems between a line and a conic sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolfram Demonstrations Project
The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-size) interactive programs called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields. It is hosted by Wolfram Research, whose stated goal is to bring computational exploration to a large population. At its launch, it contained 1300 demonstrations but has grown to over 10,000. The site won a Parents' Choice Award in 2008. Technology The Demonstrations run in '' Mathematica'' 6 or above and in '' Wolfram CDF Player'' which is a free modified version of Wolfram's ''Mathematica'' and available for Windows, Linux and macOS and can operate as a web browser plugin. They typically consist of a very direct user interface to a graphic or visualization, which dynamically recomputes in response to user actions such as moving a slider, clicking a button, or dragging a piece of graphics. Each Demonstration also has a brief description of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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