Solution
= Solution
The value $3$ occurs at $x=1,5,9$. Projecting onto that measurement outcome and normalizing leaves the <periodic coset state>
$$
\boxed{|\alpha\rangle=\frac1{\sqrt3}
\left(|1\rangle+|5\rangle+|9\rangle\right).}
$$
= Solution
The value $3$ occurs at $x=1,5,9$. Projecting onto that measurement outcome and normalizing leaves the <periodic coset state>
$$
\boxed{|\alpha\rangle=\frac1{\sqrt3}
\left(|1\rangle+|5\rangle+|9\rangle\right).}
$$