Let $n\geq2$. Is it true that the minimax problem: $$ \min_{p\in\mathcal{P}}\max_{H\in\mathcal H}p^tH\bar{p}, $$ where $\mathcal H\subset\mathcal{M}(n)$ is a strictly convex bounded subset of hermitian positive semi-definite matrices, $\mathcal{P}$ is a hyperplane of $\mathbb{C}^n$ not containing 0, has a unique solution ?
Is there a standard reference for general results about the uniqueness of a solution of minimax problems ?
Thank you.