Solution
= Solution
\b[True.] The polynomial $X^7-1$ has seven distinct roots $\zeta_7^j$ in $\mathbb C$. The <Chinese remainder theorem> gives
$$
\mathbb C[X]/(X^7-1)\cong\prod_{j=0}^6\mathbb C.
$$
The simple <modules> are exactly the seven one-dimensional evaluation <modules>, on which $X$ acts by $\zeta_7^j$. Thus there are \b[seven] up to <isomorphism>.