Segmentotope (EntityClass, 11)
From Hi.gher. Space
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- | A ''segmentochoron'' is a polychoron whose vertices lie on two parallel | + | A '''segmentochoron''' is a [[polychoron]] whose [[vertices]] lie on two [[parallel]] [[hyperplane]]s. The set of all [[convex]] segmentochora having [[regular]] polygon [[ridge]]s has been enumerated by [[Dr. Richard Klitzing]]. There are 177 of them, including some polychora from other categories (such as [[cube]] || cube, which is the same as the [[tesseract]]). The full list can be obtained from [http://www.orchidpalms.com/polyhedra/segmentochora/artConvSeg_7.pdf Klitzing's paper] (PDF format). |
- | ==Nomenclature== | + | == Nomenclature == |
+ | A segmentochoron is denoted by the notation A || B, where A and B are lower-dimensional polytopes. A and B are usually polyhedra, although one of them can be lower-dimensional, as is the case with the [[wedge]]s and [[pyramid]]s. | ||
- | + | Some segmentochora may have multiple designations, for example, ([[triangular_prism]] || [[hexagonal_prism]]) is the same as ([[triangular_cupola]] || triangular_cupola). Where multiple names are possible, the name listed by Klitzing takes precedence. | |
- | + | ||
- | Some segmentochora may have multiple designations, for example, triangular_prism||hexagonal_prism is the same as triangular_cupola||triangular_cupola. Where multiple names are possible, the name listed by Klitzing takes precedence. | + | |
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+ | == Properties == | ||
Below are some useful properties of selected segmentochora. Klitzing's numbering is written as "K 4.''n''", as given in his PhD dissertation. Measurements are given in terms of E, the edge length. | Below are some useful properties of selected segmentochora. Klitzing's numbering is written as "K 4.''n''", as given in his PhD dissertation. Measurements are given in terms of E, the edge length. | ||
- | <!-- | + | <!-- NOTE: this is intended to list common properties of certain segmentotopes that might be useful in the search for CRF polychora --> |
- | NOTE: this is intended to list common properties of certain segmentotopes that might be useful in the search for CRF polychora | + | |
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- | Dichoral angle between triangular prism and decagonal prism: asin(sqrt((5-2*sqrt(5))/15)) ≈ 10.81° | + | <table class="wikitable"> |
+ | <tr><th>#</th><th>Name(s)</th><th>Cells</th><th>Values</th></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.7 | ||
+ | </td><td> | ||
+ | '''[[digon]] || [[square_pyramid]]''' | ||
+ | *[[triangular prism pyramid]] (K 4.7.2) | ||
+ | *[[point]] || [[trigonal_prism]] | ||
+ | </td><td> | ||
+ | *2 [[tetrahedra]] | ||
+ | *3 square pyramids | ||
+ | *1 trigonal prism | ||
+ | </td><td> | ||
+ | *Height of triangular prism pyramid: E*sqrt(5/12) | ||
+ | *Dichoral angle between tetrahedron and triangular prism: atan(sqrt(5/3)) ≈ 52.24° | ||
+ | *Dichoral angle between square pyramid and triangular prism: atan(sqrt(5)) ≈ 65.91° | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.26 | ||
+ | </td><td> | ||
+ | '''[[square]] || square_pyramid''' | ||
+ | *[[cubical pyramid]] | ||
+ | *point || [[cube]] | ||
+ | *square prism pyramid | ||
+ | </td><td> | ||
+ | *6 square pyramids | ||
+ | *1 cube | ||
+ | </td><td> | ||
+ | *Dichoral angle between square pyramid and cube: 45° (exact) | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.45 | ||
+ | </td><td> | ||
+ | '''[[triangular_cupola]] || triangular_cupola''' | ||
+ | *[[triangular_prism]] || [[hexagonal_prism]] | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance between hexagonal prism and antipodal triangular prism: E*sqrt(2/3). (Same as the height of a triangular cupola.) | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.51 | ||
+ | </td><td> | ||
+ | '''[[hexagon]] || [[trigonal_cupola]]''' | ||
+ | *[[triangle]] || hexagonal prism | ||
+ | *[[trigonal orthobicupolic ring]] | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance from hexagonal prism to triangle: E*sqrt(5/12) | ||
+ | *Dichoral angle between trigonal cupola and hexagonal prism: atan(sqrt(5/3)) ≈ 52.23° | ||
+ | *Dichoral angle between square pyramid and hexagonal prism: atan(sqrt(5/2)) ≈ 57.69° | ||
+ | *Dichoral angle between triangular prism and hexagonal prism: atan(sqrt(5)) ≈ 65.91° | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.69 | ||
+ | </td><td> | ||
+ | '''[[square_cupola]] || square_cupola''' | ||
+ | *'''cube || [[octagonal_prism]]''' | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance between octagonal prism and antipodal cube: E*sqrt(2)/2. (Same as height of square cupola.) | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.105 | ||
+ | </td><td> | ||
+ | '''[[octagon]] || square_cupola''' | ||
+ | *[[square]] || octagonal_prism | ||
+ | *[[square orthobicupolic ring]] | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance from octagonal prism to square: E*sqrt(2)/2 | ||
+ | *Dichoral angle between square cupola and octagonal prism: 45° (exact) | ||
+ | *Dichoral angle between square pyramid and octagonal prism: asin(sqrt(2/3)) ≈ 54.74° | ||
+ | *Dichoral angle between triangular prism and octagonal prism: 45° (exact) | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.117 | ||
+ | </td><td> | ||
+ | '''[[pentagonal_cupola]] || pentagonal_cupola''' | ||
+ | *[[pentagonal_prism]] || [[decagonal_prism]] | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance between pentagonal prism and decagonal prism: E*(sqrt(2*sqrt(2*(3*sqrt(5)+7)) - (12*sqrt(5)+20)/5)/2). (Same as height of pentagonal cupola.) | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.141 | ||
+ | </td><td> | ||
+ | '''[[pentagon]] || [[pentagonal_pyramid]]''' | ||
+ | *[[point]] || pentagonal_prism | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance between pentagonal prism and antipodal point: (E/2)*sqrt((5-2*sqrt(5))/5) | ||
+ | *Dichoral angle between pentagonal pyramid and pentagonal prism: 18° (exact) | ||
+ | *Dichoral angle between square pyramid and pentagonal prism: atan(sqrt(5)-2) ≈ 13.28° | ||
+ | </td></tr> | ||
+ | <tr style="vertical-align: top;"><td> | ||
+ | K 4.165 | ||
+ | </td><td> | ||
+ | '''[[decagon]] || [[pentagonal_cupola]]''' | ||
+ | *pentagon || [[decagonal_prism]] | ||
+ | *[[pentagonal orthobicupolic ring]] | ||
+ | </td><td> | ||
+ | </td><td> | ||
+ | *Distance between decagonal prism and pentagon: (E/2)*sqrt((5-2*sqrt(5))/5) | ||
+ | *Dichoral angle between pentagonal cupola and decagonal prism: 18° (exact) | ||
+ | *Dichoral angle between square pyramid and decagonal prism: atan(sqrt(9-4*sqrt(5))) ≈ 13.28° | ||
+ | *Dichoral angle between triangular prism and decagonal prism: asin(sqrt((5-2*sqrt(5))/15)) ≈ 10.81° | ||
+ | </td></tr> | ||
+ | </table> |
Revision as of 19:57, 9 January 2012
A segmentochoron is a polychoron whose vertices lie on two parallel hyperplanes. The set of all convex segmentochora having regular polygon ridges has been enumerated by Dr. Richard Klitzing. There are 177 of them, including some polychora from other categories (such as cube || cube, which is the same as the tesseract). The full list can be obtained from Klitzing's paper (PDF format).
Nomenclature
A segmentochoron is denoted by the notation A || B, where A and B are lower-dimensional polytopes. A and B are usually polyhedra, although one of them can be lower-dimensional, as is the case with the wedges and pyramids.
Some segmentochora may have multiple designations, for example, (triangular_prism || hexagonal_prism) is the same as (triangular_cupola || triangular_cupola). Where multiple names are possible, the name listed by Klitzing takes precedence.
Properties
Below are some useful properties of selected segmentochora. Klitzing's numbering is written as "K 4.n", as given in his PhD dissertation. Measurements are given in terms of E, the edge length.
# | Name(s) | Cells | Values |
---|---|---|---|
K 4.7 |
|
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|
K 4.26 |
square || square_pyramid
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K 4.45 |
triangular_cupola || triangular_cupola |
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K 4.51 |
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K 4.69 |
square_cupola || square_cupola
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K 4.105 |
octagon || square_cupola
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| |
K 4.117 |
pentagonal_cupola || pentagonal_cupola |
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K 4.141 |
pentagon || pentagonal_pyramid
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| |
K 4.165 |
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