Affine integral geometry and convex bodies

Given a convex body Q in Euclidean n‐dimensional space, the affine invariant measure of the set of pairs of parallel hyperplanes containing Q is an affine invariant J(Q) of Q, which, for ellipsoids, parallelepipeds and possibly for simplices of any dimensions, is proportional to V−1, where V represe...

Descripción completa

Detalles Bibliográficos
Publicado: 1988
Materias:
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00222720_v151_n3_p229_Santalo
http://hdl.handle.net/20.500.12110/paper_00222720_v151_n3_p229_Santalo
Aporte de:
id paper:paper_00222720_v151_n3_p229_Santalo
record_format dspace
spelling paper:paper_00222720_v151_n3_p229_Santalo2023-06-08T14:48:41Z Affine integral geometry and convex bodies Affine transformations breadth convex bodies invariant densities n‐ellipsoids n‐parallelepipeds n‐simplices parallel hyperplanes r‐flats Given a convex body Q in Euclidean n‐dimensional space, the affine invariant measure of the set of pairs of parallel hyperplanes containing Q is an affine invariant J(Q) of Q, which, for ellipsoids, parallelepipeds and possibly for simplices of any dimensions, is proportional to V−1, where V represents the volume of Q. Consequently, for the kind of bodies mentioned, it is possible to estimate V−1 from its breadth measured in uniform random directions. If the boundary of Q is of class C2, we obtain a set of affine invariants Jh(Q) (h = any integer) which is easily calculable for ellipsoids. In particular, J‐n(Q) coincides with J(Q) and J‐(n+1)(Q) is the affine invariant measure of all pairs of parallel hyperplanes that ‘support’ Q as described by Firey(1972, 1985), Schneider (1978, 1979) and Weil (1979, 1981). For a general convex body Q the values of Jh(Q) cannot be expressed in terms of simple metric invariants (such as volume, surface area, breadth, width) and this justifies the study in the last section of certain inequalities between them. 1988 Blackwell Science Ltd 1988 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00222720_v151_n3_p229_Santalo http://hdl.handle.net/20.500.12110/paper_00222720_v151_n3_p229_Santalo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Affine transformations
breadth
convex bodies
invariant densities
n‐ellipsoids
n‐parallelepipeds
n‐simplices
parallel hyperplanes
r‐flats
spellingShingle Affine transformations
breadth
convex bodies
invariant densities
n‐ellipsoids
n‐parallelepipeds
n‐simplices
parallel hyperplanes
r‐flats
Affine integral geometry and convex bodies
topic_facet Affine transformations
breadth
convex bodies
invariant densities
n‐ellipsoids
n‐parallelepipeds
n‐simplices
parallel hyperplanes
r‐flats
description Given a convex body Q in Euclidean n‐dimensional space, the affine invariant measure of the set of pairs of parallel hyperplanes containing Q is an affine invariant J(Q) of Q, which, for ellipsoids, parallelepipeds and possibly for simplices of any dimensions, is proportional to V−1, where V represents the volume of Q. Consequently, for the kind of bodies mentioned, it is possible to estimate V−1 from its breadth measured in uniform random directions. If the boundary of Q is of class C2, we obtain a set of affine invariants Jh(Q) (h = any integer) which is easily calculable for ellipsoids. In particular, J‐n(Q) coincides with J(Q) and J‐(n+1)(Q) is the affine invariant measure of all pairs of parallel hyperplanes that ‘support’ Q as described by Firey(1972, 1985), Schneider (1978, 1979) and Weil (1979, 1981). For a general convex body Q the values of Jh(Q) cannot be expressed in terms of simple metric invariants (such as volume, surface area, breadth, width) and this justifies the study in the last section of certain inequalities between them. 1988 Blackwell Science Ltd
title Affine integral geometry and convex bodies
title_short Affine integral geometry and convex bodies
title_full Affine integral geometry and convex bodies
title_fullStr Affine integral geometry and convex bodies
title_full_unstemmed Affine integral geometry and convex bodies
title_sort affine integral geometry and convex bodies
publishDate 1988
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00222720_v151_n3_p229_Santalo
http://hdl.handle.net/20.500.12110/paper_00222720_v151_n3_p229_Santalo
_version_ 1768541784739151872