772 Symmetry
   HOME

TheInfoList



OR:

In
geometry Geometry (; ) is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. Geometry is, along with arithmetic, one of the oldest branches of mathematics. A mathematician w ...
, the truncated order-4 heptagonal tiling is a uniform tiling of the
hyperbolic plane In mathematics, hyperbolic geometry (also called Lobachevskian geometry or Bolyai– Lobachevskian geometry) is a non-Euclidean geometry. The parallel postulate of Euclidean geometry is replaced with: :For any given line ''R'' and point ''P' ...
. It has
Schläfli symbol In geometry, the Schläfli symbol is a notation of the form \ that defines List of regular polytopes and compounds, regular polytopes and tessellations. The Schläfli symbol is named after the 19th-century Swiss mathematician Ludwig Schläfli, wh ...
of t.


Constructions

There are two uniform constructions of this tiling, first by the ,4
kaleidoscope A kaleidoscope () is an optical instrument with two or more reflecting surfaces (or mirrors) tilted to each other at an angle, so that one or more (parts of) objects on one end of these mirrors are shown as a symmetrical pattern when viewed fro ...
, and second by removing the last mirror, ,4,1+ gives ,7 (*772).


Symmetry

There is only one simple subgroup ,7sup>+, index 2, removing all the mirrors. This symmetry can be doubled to
742 symmetry In geometry, the truncated tetraheptagonal tiling is a uniform tiling of the hyperbolic plane. It has Schläfli symbol of tr. Images Poincaré disk projection, centered on 14-gon: : Symmetry The dual to this tiling represents the fundamental d ...
by adding a bisecting mirror.


Related polyhedra and tiling


References

* John H. Conway, Heidi Burgiel, Chaim Goodman-Strauss, ''The Symmetries of Things'' 2008, (Chapter 19, The Hyperbolic Archimedean Tessellations) *


See also

*
Uniform tilings in hyperbolic plane In hyperbolic geometry, a uniform hyperbolic tiling (or regular, quasiregular or semiregular hyperbolic tiling) is an edge-to-edge filling of the hyperbolic plane which has regular polygons as Face (geometry), faces and is vertex-transitive (Tran ...
*
List of regular polytopes This article lists the regular polytopes in Euclidean, spherical and hyperbolic spaces. Overview This table shows a summary of regular polytope counts by rank. There are no Euclidean regular star tessellations in any number of dimensions. ...


External links

* *
Hyperbolic and Spherical Tiling Gallery


* ttp://www.plunk.org/~hatch/HyperbolicTesselations Hyperbolic Planar Tessellations, Don Hatch Heptagonal tilings Hyperbolic tilings Isogonal tilings Order-4 tilings Truncated tilings Uniform tilings {{hyperbolic-geometry-stub