Arveson extreme points span free spectrahedra

Eric Evert, J. William Helton

Let $S{M}_n(\mathbb{R}{)}^g$ denote $g$-tuples of $n\times n$ real symmetric matrices. Given tuples $X=(X_1,\dots ,X_g)\in S{M}_{n_1}(\mathbb{R}{)}^g$ and $Y=(Y_1, \dots, Y_g) \in SM_{…