The Dimension Landscape of Bivariate C2 Splines
Abstract
Schumaker's lower bound incorporates local geometric corrections and provides insight into the dimensions of bivariate spline spaces. Building on this bound, we study bivariate C2 spline dimensions from three perspectives: universal attainment, generic attainment, and geometric jumps. We prove universal attainment in degree seven for every legal realization of every triangulation. We prove generic attainment in degrees five and six for every fixed combinatorial triangulation and give explicit polynomial conditions certifying generic failure on fixed triangulations in degrees three and four. For geometric jumps with matching local direction types at corresponding interior vertices, we prove nonexistence in degree seven and construct examples in degrees three and five. In degree six, universal attainment and the existence of such geometric jumps remain open questions.
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BibTeX
@misc{wu2026dimension,
title = {{The Dimension Landscape of Bivariate $C^2$ Splines}},
author = {Xinyu Wu and Jiansong Deng},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27814},
eprint = {2610.27814},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27814},
}
RIS
TY - UNPB
TI - The Dimension Landscape of Bivariate C^2 Splines
AU - Xinyu Wu
AU - Jiansong Deng
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.27814
UR - https://arxiv.org/abs/2610.27814
AB - Schumaker's lower bound incorporates local geometric corrections and provides insight into the dimensions of bivariate spline spaces. Building on this bound, we study bivariate C^2 spline dimensions from three perspectives: universal attainment, generic attainment, and geometric jumps. We prove universal attainment in degree seven for every legal realization of every triangulation. We prove generic attainment in degrees five and six for every fixed combinatorial triangulation and give explicit polynomial conditions certifying generic failure on fixed triangulations in degrees three and four. For geometric jumps with matching local direction types at corresponding interior vertices, we prove nonexistence in degree seven and construct examples in degrees three and five. In degree six, universal attainment and the existence of such geometric jumps remain open questions.
ER -