2 problems

Let $\sigma=\{a,b,c\pm di\}$ satisfy the preceding case assumptions: $\{a,c\pm di\}$ is $\mathcal{R}$, $a+2c>0$, $a-c-\sqrt{3}d=0$, and $b>\frac{a+2c}{3}$. Thus…

Let $\sigma$ be a spectrum, equivalently the spectrum of a polynomial $P(x)$. Write $\mathcal{R}$ for realizability, $\mathcal{IR}$ for irreducible realizability, and SS for the st…