1. Fan Valuations and Spherical Intrinsic Volumes.
- Author
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Backman, Spencer, Manecke, Sebastian, and Sanyal, Raman
- Subjects
- *
METRIC projections , *SPHERICAL functions , *VALUATION , *POLYNOMIALS , *GENERALIZATION - Abstract
We generalize valuations on polyhedral cones to valuations on (plane) fans. For fans induced by hyperplane arrangements, we show a correspondence between rotation-invariant valuations and deletion– restriction invariants. In particular, we define a characteristic polynomial for fans in terms of spherical intrinsic volumes and show that it coincides with the usual characteristic polynomial in the case of hyperplane arrangements. This gives a simple deletion–restriction proof of a result of Klivans–Swartz. The metric projection of a cone is a piecewise-linear map, whose underlying fan prompts a generalization of spherical intrinsic volumes to indicator functions. We show that these intrinsic indicators yield valuations that separate polyhedral cones. Applied to hyperplane arrangements, this generalizes a result of Kabluchko on projection volumes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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