Примеры использования Desargues на Английском языке и их переводы на Русский язык
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The Desargues graph is Hamiltonian and can be constructed from the ICF notation: 5.
The bipartite double cover of the Petersen graph is the Desargues graph: K2× G(5,2) G10,3.
The Desargues graph is the Levi graph of the Desargues configuration, composed of 10 points and 10 lines.
There are several different ways of constructing the Desargues graph: It is the generalized Petersen graph G10, 3.
Like the Desargues configuration there are 3 points on each line and 3 lines passing through each point.
Because of the symmetries and self-duality of the Desargues configuration, the Desargues graph is a symmetric graph.
The Desargues graph can also be viewed as the generalized Petersen graph G(10,3) or the bipartite Kneser graph with parameters 5,2.
This is most significant for projective planes due to the universal validity of Desargues' theorem in higher dimensions.
Pascal and Desargues also studied curves, but from the purely geometrical point of view: the analog of the Greek ruler and compass construction.
This construction is closely related to the property that every projective plane that can be embedded into a projective space obeys Desargues' theorem.
The Desargues graph is a symmetric graph: it has symmetries that take any vertex to any other vertex and any edge to any other edge.
The tensor product G×K2 is a bipartite graph, called the bipartite double cover of G. The bipartite double cover of the Petersen graph is the Desargues graph: K2× G(5,2) G10,3.
The Desargues graph has rectilinear crossing number 6, and is the smallest cubic graph with that crossing number sequence A110507 in the OEIS.
Although certain specific configurations had been studied earlier(for instance by Thomas Kirkman in 1849), the formal study of configurations was first introduced by Theodor Reye in 1876, in the second edition of his book Geometrie der Lage,in the context of a discussion of Desargues' theorem.
The Levi graph of the Desargues configuration, a graph having one vertex for each point or line in the configuration, is known as the Desargues graph.
There also exist eight other(103103) configurations(that is, sets of points and lines in the Euclidean plane with three lines per point and three points per line)that are not incidence-isomorphic to the Desargues configuration, one of which is shown at right.
In geometry, the Desargues configuration is a configuration of ten points and ten lines, with three points per line and three lines per point.
Desargues' theorem in geometry states that these two conditions are equivalent: if two triangles are in perspective centrally then they must also be in perspective axially, and vice versa.
Due to this construction, the Fano plane is considered to be a Desarguesian plane, even thoughthe plane is too small to contain a non-degenerate Desargues configuration which requires 10 points and 10 lines.
Desargues' theorem, named after 17th-century French mathematician Gérard Desargues, describes a set of points and lines forming this configuration, and the configuration and the graph take their name from it.
One can interpret this product representation of the symmetry group in terms of the constructions of the Desargues graph: the symmetric group on five points is the symmetry group of the Desargues configuration, and the order-2 subgroup swaps the roles of the vertices that represent points of the Desargues configuration and the vertices that represent lines.
For instance, the Desargues graph is not only the bipartite double cover of the Petersen graph, but is also the bipartite double cover of a different graph that is not isomorphic to the Petersen graph.
As a projective configuration, the Desargues configuration has the notation(103103), meaning that each of its ten points is incident to three lines and each of its ten lines is incident to three points.
The Desargues configuration can also be defined in terms of perspective triangles, and the Reye configuration can be defined analogously from two tetrahedra that are in perspective with each other in four different ways, forming a desmic system of tetrahedra.
The Desargues graph, a 20-vertex bipartite symmetric cubic graph, is so called because it can be interpreted as the Levi graph of the Desargues configuration, with a vertex for each point and line of the configuration and an edge for every incident point-line pair.
The Desargues configuration is self-dual, meaning that it is possible to find a correspondence from points of one Desargues configuration to lines of a second configuration, and from lines of the first configuration to points of a second configuration, in such a way that all of the configuration's incidences are preserved Coxeter 1964.
The three-dimensional construction of the Desargues configuration makes these symmetries more readily apparent: if the configuration is generated from five planes in general position in three dimensions, then each of the 120 different permutations of these five planes corresponds to a symmetry of the configuration Barnes 2012.
Although Desargues's theorem chooses different roles for these ten lines and points, the Desargues configuration itself is more symmetric: any of the ten points may be chosen to be the center of perspectivity, and that choice determines which six points will be the vertices of triangles and which line will be the axis of perspectivity.
Although it may be embedded in two dimensions, the Desargues configuration has a very simple construction in three dimensions: for any configuration of five planes in general position in Euclidean space, the ten points where three planes meet and the ten lines formed by the intersection of two of the planes together form an instance of the configuration Barnes 2012.