Equal-characteristic complete discretely valued field
= Equal-characteristic complete discretely valued field
If a complete discretely valued field $K$ has positive characteristic and perfect residue field $k$, its <Teichmuller lift> is the unique ring section $k\to\mathcal O_K$. A choice of <uniformizer> $t$ then gives
$$
\mathcal O_K\cong k[[t]],
\qquad K\cong k((t)).
$$