TY - JOUR
T1 - Crofton formulas in pseudo-Riemannian space forms
AU - Bernig, Andreas
AU - Faifman, Dmitry
AU - Solanes, Gil
N1 - Funding Information:
We wish to thank Gautier Berck for several inspiring talks and discussions, and the referee for numerous valuable comments which helped improve the exposition. A.B. was supported by DFG grant BE 2484/5-2. D.F. was supported by ISF Grant 1750/20. G.S. was supported by FEDER/MICINN grant PGC2018-095998-B-I00 and the Serra Húnter Programme.
Publisher Copyright:
© 2022 The Author(s).
PY - 2022/10/28
Y1 - 2022/10/28
N2 - Crofton formulas on simply connected Riemannian space forms allow the volumes, or more generally the Lipschitz-Killing curvature integrals of a submanifold with corners, to be computed by integrating the Euler characteristic of its intersection with all geodesic submanifolds. We develop a framework of Crofton formulas with distributions replacing measures, which has in its core Alesker's Radon transform on valuations. We then apply this framework, and our recent Hadwiger-Type classification, to compute explicit Crofton formulas for all isometry-invariant valuations on all pseudospheres, pseudo-Euclidean and pseudohyperbolic spaces. We find that, in essence, a single measure which depends analytically on the metric, gives rise to all those Crofton formulas through its distributional boundary values at parts of the boundary corresponding to the different indefinite signatures. In particular, the Crofton formulas we obtain are formally independent of signature.
AB - Crofton formulas on simply connected Riemannian space forms allow the volumes, or more generally the Lipschitz-Killing curvature integrals of a submanifold with corners, to be computed by integrating the Euler characteristic of its intersection with all geodesic submanifolds. We develop a framework of Crofton formulas with distributions replacing measures, which has in its core Alesker's Radon transform on valuations. We then apply this framework, and our recent Hadwiger-Type classification, to compute explicit Crofton formulas for all isometry-invariant valuations on all pseudospheres, pseudo-Euclidean and pseudohyperbolic spaces. We find that, in essence, a single measure which depends analytically on the metric, gives rise to all those Crofton formulas through its distributional boundary values at parts of the boundary corresponding to the different indefinite signatures. In particular, the Crofton formulas we obtain are formally independent of signature.
KW - Crofton formula
KW - Lipschitz-Killing curvature measures
KW - pseudo-Riemannian space form
KW - valuation
UR - http://www.scopus.com/inward/record.url?scp=85142322840&partnerID=8YFLogxK
U2 - 10.1112/S0010437X22007722
DO - 10.1112/S0010437X22007722
M3 - Article
AN - SCOPUS:85142322840
SN - 0010-437X
VL - 158
SP - 1935
EP - 1979
JO - Compositio Mathematica
JF - Compositio Mathematica
IS - 10
ER -