Square (EntityTopic, 20)
From Hi.gher. Space
(Difference between revisions)
(Added homology groups. This might look better as a table. Also how do I get blackboard bold and the circle plus in this wiki?) |
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1-frame (four line segments): | 1-frame (four line segments): | ||
- | H<sub>0</sub> = Z | + | H<sub>0</sub> = Z <br/> |
H<sub>1</sub> = Z | H<sub>1</sub> = Z | ||
2-frame (solid square): | 2-frame (solid square): | ||
H<sub>0</sub> = Z | H<sub>0</sub> = Z | ||
- | |||
== Brick == | == Brick == |
Revision as of 07:36, 24 November 2009
A square is a two-dimensional hypercube.
Squares are the most common base for two-dimensional manifolds and polyominoes.
Equations
- Variables:
l ⇒ length of edges of the square
- The radial slices θ of a square are:
[:x,:y] ⇒ digon of length lsin(45° + (θ % 90°)√2
Homology Groups
Any unstated homology group is the trivial group 0.
0-frame (four points): H0 = 4Z
1-frame (four line segments):
H0 = Z
H1 = Z
2-frame (solid square): H0 = Z
Brick
The square is a brick with one unique point at (1,1). It represents the Cartesian product and the MAX function.
Segmentation
The square of side 2 may be segmented into 4× triangle with sides 2, 2×22-1 and angles 2×45°, 90°.
Use
Square faces are found in these trishapes on FGwiki:
- Cube (6×, 100%)
- Triangular prism (3×, 60%)
- Cuboctahedron (6×, 43%)
- Octahedral truncate (6×, 43%)
- Square antiprism (2×, 20%)
- Square pyramid (1×, 20%)
- Cubic snub (6×, 16%)
See also
Hypercubes |
point • digon • square • cube • geochoron • geoteron • geopeton |
Notable Dishapes | |
Flat: | triangle • square • pentagon • hexagon • octagon • decagon |
Curved: | circle |
1. x Digon | 2. [xy] Square | 3. Diamond |
List of bracketopes |