# Properties

 Label 1.6.J.8.3b Name $$J(J(E_4),E_4)$$ Weight $1$ Degree $6$ Real dimension $4$ Components $8$ Contained in $$\mathrm{USp}(6)$$ Identity component $$\mathrm{U}(1)\times\mathrm{SU}(2)_2$$ Component group $$D_4$$

## Invariants

 Weight: $1$ Degree: $6$ $\mathbb{R}$-dimension: $4$ Components: $8$ Contained in: $\mathrm{USp}(6)$ Rational: yes

## Identity component

 Name: $\mathrm{U}(1)\times\mathrm{SU}(2)_2$ $\mathbb{R}$-dimension: $4$ Description: $\left\{\begin{bmatrix}A&0&0\\0&B&0\\0&0&\overline{B}\end{bmatrix}: A\in\mathrm{U}(1)\subseteq\mathrm{SU}(2),B\in\mathrm{SU}(2)\right\}$ Symplectic form: $\begin{bmatrix}J_2&0&0\\0&0&I_2\\0&-I_2&0\end{bmatrix},\ J_2:=\begin{bmatrix}0&1\\-1&0\end{bmatrix}$ Hodge circle: $\mathrm{diag}(u,\bar u, u,\bar u,\bar u,u)$

## Component group

 Name: $D_4$ Order: $8$ Abelian: no Generators: $\begin{bmatrix}1 & 0 & 0 & 0 & 0 & 0 \\0 & 1 & 0 & 0 & 0 & 0 \\0 & 0 & \zeta_{8}^{1} & 0 & 0 & 0 \\0 & 0 & 0 & \zeta_{8}^{1} & 0 & 0 \\0 & 0 & 0 & 0 & \zeta_{8}^{7} & 0 \\0 & 0 & 0 & 0 & 0 & \zeta_{8}^{7} \\\end{bmatrix}, \begin{bmatrix}0 & 1 & 0 & 0 & 0 & 0 \\-1 & 0 & 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 & 0 & 1 \\0 & 0 & 0 & 0 & -1 & 0 \\0 & 0 & 0 & -1 & 0 & 0 \\0 & 0 & 1 & 0 & 0 & 0 \\\end{bmatrix}$