Multiplicative group scheme
= Multiplicative group scheme
{title2=$\mathbb G_{m,A}=\operatorname{Spec}A[t,t^{-1}]$}
The multiplicative group <scheme> represents <units>: its $R$-points are $R^\times$. Multiplication is specified by $t\mapsto t\otimes t$ on the coordinate <ring>. It is the <principal open subset> $D(t)$ of the <affine line> and the one-dimensional split <algebraic torus>.
// Target: ringed-space.bigb