A surface area formula for compact hypersurfaces in Rn
The classical Cauchy surface area formula states that the surface area of the boundary ∂ K = Σ of any n -dimensional convex body in the n -dimensional Euclidean space R n can be obtained by the average of the projected areas of Σ along all directions in S n − 1 . In this note, we generalize the form...
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Published in | Journal of inequalities and applications Vol. 2024; no. 1; p. 44 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
Cham
Springer International Publishing
01.12.2024
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | The classical Cauchy surface area formula states that the surface area of the boundary
∂
K
=
Σ
of any
n
-dimensional convex body in the
n
-dimensional Euclidean space
R
n
can be obtained by the average of the projected areas of Σ along all directions in
S
n
−
1
. In this note, we generalize the formula to the boundary of arbitrary
n
-dimensional submanifold in
R
n
by introducing a natural notion of projected areas along any direction in
S
n
−
1
. This surface area formula derived from the new notion coincides with not only the result of the Crofton formula but also with that of De Jong (Math. Semesterber. 60(1):81–83,
2013
) by using a tubular neighborhood. We also define the projected
r
-volumes of Σ onto any
r
-dimensional subspaces and obtain a recursive formula for mean projected
r
-volumes of Σ. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 |
ISSN: | 1025-5834 1029-242X |
DOI: | 10.1186/s13660-024-03129-x |