Take the 2-minute tour ×  Let $A=k[[t]]$ Let $B$ a flat
$A$-finite algebra which is etale and Galois at the generic
point.  Then by Artin lemma 3.12 (ii) in his IHES paper on
approximation, we know that there exists an integer $c$ such
that:  if we have an other $A$-finite flat algebra generically
étale and Galois $B'$ such that $B/\pi^{c}\cong B'/\pi^{c}$
implies $B\cong B'$.  Can we be more precise about the value of
$c$ for exemple how can we relate it to $B$?  Moreover, can we
get a isomorphism $\phi: B\cong B'$ which lifts the isomorphism
mod $\pi^{c}$?  share|improve this question add comment   Your
Answer    Browse other questions tagged or ask your own
question.