Cases

Conditions

Bounds

5.th case of Sparse

$\left|a_0\right|+\cdots +\left|a_3\right|<1$

$\left|\lambda \right|\le 1$

Cauchy

${\Vert \mathrm{.}\Vert }_{\infty }$

$\left|\lambda \right|\le 1.04$

Montel

${\Vert \mathrm{.}\Vert }_1$

$\left|\lambda \right|\le 1$

Carmichel-Mason

${\Vert \mathrm{.}\Vert }_2$

$\left|\lambda \right|\le 1.0027462291$