Let
be a
valued field. We reinterpret some results of MacLane and Vaquié on extensions of
to valuations on the
polynomial ring
.
We introduce certain MacLane–Vaquié chains constructed as a mixture
of ordinary and limit augmentations of valuations. Every valuation
on
is a limit
(in a certain sense) of a countable MacLane–Vaquié chain. This chain underlying
is essentially
unique and contains discrete arithmetic data yielding an explicit description of the graded algebra of
as an algebra over the
graded algebra of
.