Formal power series
= Formal power series
{title2=$R[[T]]$}
{wiki}
The <formal power series ring> $R[[T]]$ consists of all expressions $\sum_{n\geq0}a_nT^n$ with $a_n\in R$. Addition is coefficientwise, while multiplication uses the <Cauchy product>; no analytic convergence is required.
= Formal power series ring
{synonym}