4 problems

For $k\in\mathbb N$, let $s_{\mathbb R}(2,2,(2,k+1))$ and $s_{\mathbb C}(2,2,(2,k+1))$ be the minimum compatibility degrees for one dichotomic and one $(k+1)$-outcome measurement o…

Four-variable matrix-cube optimum conjecture. The optimal value is $\sqrt{13}/2$. This is equivalent to the conjectured optimality of the four-dichotomic-qubit compatibility bound;…

Let $s_{\mathbb C}(2,4)$ denote the minimum compatibility degree of four dichotomic measurements on a complex qubit. Four-dichotomic-qubit compatibility-degree conjecture. … The va…

Let $k\in\mathbb N$ and $d\geq 2$. The minimum compatibility degree $s_{\mathbb C}(d,2,(2,k+1))$ concerns one dichotomic measurement and one measurement with $k+1$ outcomes on a…