Theta group
= Theta group
{title2=$\Gamma_\theta$}
The theta group is $\Gamma_\theta=\Gamma(2)\cup\Gamma(2)S$. It is generated by $T^2$ and $S$ and has index three in the <modular group>.
= Theta group
{title2=$\Gamma_\theta$}
The theta group is $\Gamma_\theta=\Gamma(2)\cup\Gamma(2)S$. It is generated by $T^2$ and $S$ and has index three in the <modular group>.