Local Maxima of the Entrywise ${\ell }_4$ Norm on the Orthogonal Group

Dian Jin

We classify the local maximizers of the entrywise fourth-power objective \[ Q\longmapsto \lVert Q\rVert_4^4 =\sum_{i,j=1}^r q_{ij}^4 \] over the real orthogonal group $\mathcal O(r…