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arXiv · 2202.09078

Clifford systems, harmonic maps and metrics with non-negative curvature

Chao Qian·Zizhou Tang·Wenjiao Yan
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Abstract

Associated with a symmetric Clifford system $\{P_0, P_1,\cdots, P_{m}\}$ on $\mathbb{R}^{2l}$, there is a canonical vector bundle $\eta$ over $S^{l-1}$. For $m=4$ and $8$, we construct explicitly its characteristic map, and determine completely when the sphere bundle $S(\eta)$ associated to $\eta$ admits a cross-section. These generalize the results in \cite{St51} and \cite{Ja58}. As an application, we establish new harmonic representatives of certain elements in homotopy groups of spheres (cf. \cite{PT97} \cite{PT98}). By a suitable choice of Clifford system, we construct a metric of non-negative curvature on $S(\eta)$ which is diffeomorphic to the inhomogeneous focal submanifold $M_+$ of OT-FKM type isoparametric hypersurfaces with $m=3$.

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Chao Qian, Zizhou Tang, Wenjiao Yan. 2022-02-18. Clifford systems, harmonic maps and metrics with non-negative curvature. https://arxiv.org/abs/2202.09078

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