Coordinate ring of an affine toric variety (source code)

= Coordinate ring of an affine toric variety
{title2=$\mathbb C[\sigma^\vee\cap M]$}

The coordinate ring of $U_\sigma$ is generated by the characters $\chi^m$ for lattice points $m\in\sigma^\vee\cap M$, with multiplication $\chi^m\chi^{m'}=\chi^{m+m'}$.