Truncated triapeirogonal tiling explained

In geometry, the truncated triapeirogonal tiling is a uniform tiling of the hyperbolic plane with a Schläfli symbol of tr.

Symmetry

The dual of this tiling represents the fundamental domains of [∞,3], *∞32 symmetry. There are 3 small index subgroup constructed from [∞,3] by mirror removal and alternation. In these images fundamental domains are alternately colored black and white, and mirrors exist on the boundaries between colors.

A special index 4 reflective subgroup, is [(∞,∞,3)], (*∞∞3), and its direct subgroup [(∞,∞,3)]+, (∞∞3), and semidirect subgroup [(∞,∞,3<sup>+</sup>)], (3*∞).[1] Given [∞,3] with generating mirrors, then its index 4 subgroup has generators .

An index 6 subgroup constructed as [∞,3*], becomes [(∞,∞,∞)], (*∞∞∞).

Small index subgroups of [∞,3], (*∞32)
Index1234681224
Diagrams
Coxeter
(orbifold)
[∞,3]
=
(*∞32)
[1<sup>+</sup>,∞,3]
=
(
  • ∞33
)
[∞,3<sup>+</sup>]

(3*∞)
[∞,∞]

(
  • ∞∞2
)
[(∞,∞,3)]

(
  • ∞∞3
)
[∞,3*]
=
(
  • 3
)
[∞,1<sup>+</sup>,∞]

(*(∞2)2)
[(∞,1<sup>+</sup>,∞,3)]

(*(∞3)2)
[1<sup>+</sup>,∞,∞,1<sup>+</sup>]

(*∞4)
[(∞,∞,3*)]

(*∞6)
Direct subgroups
Index246812162448
Diagrams
Coxeter
(orbifold)
[∞,3]+
=
(∞32)
[∞,3<sup>+</sup>]+
=
(∞33)
[∞,∞]+

(∞∞2)
[(∞,∞,3)]+

(∞∞3)
[∞,3*]+
=
(∞3)
[∞,1<sup>+</sup>,∞]+

(∞2)2
[(∞,1<sup>+</sup>,∞,3)]+

(∞3)2
[1<sup>+</sup>,∞,∞,1<sup>+</sup>]+

(∞4)
[(∞,∞,3*)]+

(∞6)

Related polyhedra and tiling

This tiling can be considered a member of a sequence of uniform patterns with vertex figure (4.6.2p) and Coxeter-Dynkin diagram . For p < 6, the members of the sequence are omnitruncated polyhedra (zonohedrons), shown below as spherical tilings. For p > 6, they are tilings of the hyperbolic plane, starting with the truncated triheptagonal tiling.

See also

References

Notes and References

  1. Norman W. Johnson and Asia Ivic Weiss, Quadratic Integers and Coxeter Groups, Can. J. Math. Vol. 51 (6), 1999 pp. 1307–1336 http://cms.math.ca/cjm/v51/weisscox8.pdf