The Hyperrigidity Conjecture for compact convex sets in $\mathbb{R}^2$

Abstract: We prove that for every compact, convex subset $K\subset\mathbb{R}<sup>2$ the operator system $A(K)$, consisting of all continuous affine functions on $K$, is hyperrigid in the C*-algebra $C(\mathrm{ex}(K))$. In particular, this result implies that the weak and strong operator topologies coincide on the set $${ T\in\mathcal{B}(H);\ T\ \mathrm{normal}\ \mathrm{and}\ \sigma(T)\subset \mathrm{ex}(K) }.$$ Our approach relies on geometric properties of $K$ and generalizes previous results by Brown.