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Difference between revisions of "Zonohedron"

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A [[Polyhedron|polyhedron]] expressible as the vector sum of finitely many segments. Zonohedra in an <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/z/z099/z099320/z0993201.png" />-dimensional space are sometimes called zonotopes. A zonohedron is a convex polyhedron; the zonohedron itself and all its faces (of all dimensions) have centres of symmetry. A sufficient condition for a convex polyhedron to be a zonohedron is that its two-dimensional faces have centres of symmetry. Any zonohedron is the projection of a cube of sufficiently high dimension. A special role is assigned in the class of centrally-symmetric convex bodies to zonoids — limiting cases of zonohedra; they admit a specific integral representation of the support function and are finite-dimensional sections of the sphere in the Banach space <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/z/z099/z099320/z0993202.png" />.
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A [[Polyhedron|polyhedron]] expressible as the vector sum of finitely many segments. Zonohedra in an $n$-dimensional space are sometimes called zonotopes. A zonohedron is a convex polyhedron; the zonohedron itself and all its faces (of all dimensions) have centres of symmetry. A sufficient condition for a convex polyhedron to be a zonohedron is that its two-dimensional faces have centres of symmetry. Any zonohedron is the projection of a cube of sufficiently high dimension. A special role is assigned in the class of centrally-symmetric convex bodies to zonoids — limiting cases of zonohedra; they admit a specific integral representation of the support function and are finite-dimensional sections of the sphere in the Banach space $L_1$.
  
 
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Zonohedra or zonotopes play an important role in convexity (projection bodies, tiling), analysis (Radon transform, vector-valued measures, subspaces of <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/z/z099/z099320/z0993203.png" />) and stochastic geometry (point processes). Modern surveys are [[#References|[a1]]]–[[#References|[a2]]].
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Zonohedra or zonotopes play an important role in convexity (projection bodies, tiling), analysis (Radon transform, vector-valued measures, subspaces of $L_1$) and stochastic geometry (point processes). Modern surveys are [[#References|[a1]]]–[[#References|[a2]]].
  
 
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<table><TR><TD valign="top">[a1]</TD> <TD valign="top">  W. Weil,  "Zonoids and related topics"  P.M. Gruber (ed.)  J.M. Wills (ed.) , ''Convexity and its applications'' , Birkhäuser  (1983)  pp. 296–317</TD></TR><TR><TD valign="top">[a2]</TD> <TD valign="top">  W. Weil,  "Zonoids and generalisations"  P.M. Gruber (ed.)  J.M. Wills (ed.) , ''Handbook of convex geometry'' , North-Holland  (1992)</TD></TR></table>
 
<table><TR><TD valign="top">[a1]</TD> <TD valign="top">  W. Weil,  "Zonoids and related topics"  P.M. Gruber (ed.)  J.M. Wills (ed.) , ''Convexity and its applications'' , Birkhäuser  (1983)  pp. 296–317</TD></TR><TR><TD valign="top">[a2]</TD> <TD valign="top">  W. Weil,  "Zonoids and generalisations"  P.M. Gruber (ed.)  J.M. Wills (ed.) , ''Handbook of convex geometry'' , North-Holland  (1992)</TD></TR></table>

Latest revision as of 14:31, 10 April 2014

A polyhedron expressible as the vector sum of finitely many segments. Zonohedra in an $n$-dimensional space are sometimes called zonotopes. A zonohedron is a convex polyhedron; the zonohedron itself and all its faces (of all dimensions) have centres of symmetry. A sufficient condition for a convex polyhedron to be a zonohedron is that its two-dimensional faces have centres of symmetry. Any zonohedron is the projection of a cube of sufficiently high dimension. A special role is assigned in the class of centrally-symmetric convex bodies to zonoids — limiting cases of zonohedra; they admit a specific integral representation of the support function and are finite-dimensional sections of the sphere in the Banach space $L_1$.

References

[1] E. Bolker, "A class of convex bodies" Trans. Amer. Math. Soc. , 145 (1969) pp. 323–345
[2] W. Weil, "Kontinuierliche Linearkombination von Strecken" Math. Z. , 148 : 1 (1976) pp. 71–84


Comments

Zonohedra or zonotopes play an important role in convexity (projection bodies, tiling), analysis (Radon transform, vector-valued measures, subspaces of $L_1$) and stochastic geometry (point processes). Modern surveys are [a1][a2].

References

[a1] W. Weil, "Zonoids and related topics" P.M. Gruber (ed.) J.M. Wills (ed.) , Convexity and its applications , Birkhäuser (1983) pp. 296–317
[a2] W. Weil, "Zonoids and generalisations" P.M. Gruber (ed.) J.M. Wills (ed.) , Handbook of convex geometry , North-Holland (1992)
How to Cite This Entry:
Zonohedron. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Zonohedron&oldid=31502
This article was adapted from an original article by V.A. Zalgaller (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article