English

Lifting iterated Frobenius over $W_n(k)$

Algebraic Geometry 2019-09-23 v2

Abstract

Let XX be a smooth scheme over a perfect field kk of positive characteristic. M.V.~Nori and V.~Srinivas studied infinitesimal liftings of Frobenius morphism F:XXF:X\to X. Namely, given a Frobenius lifting FY:YYF_Y: Y\to Y over Wn1(k)W_{n-1}(k) the obstruction of lifting FYF_Y over Wn(k)W_n(k) is a class in H1(X,TX\tensorB1ΩX/k1)H^1(X, T_X\tensor B_1\Omega^1_{X/k}). We give a modified version of their theory and applications, in which we consider lifting (n1)(n-1)th iterated Frobenius Fn1:XXF^{n-1}:X\to X directly over Wn(k)W_n(k).

Keywords

Cite

@article{arxiv.1909.08900,
  title  = {Lifting iterated Frobenius over $W_n(k)$},
  author = {Yukihide Takayama},
  journal= {arXiv preprint arXiv:1909.08900},
  year   = {2019}
}

Comments

Proposition 17 is false, which is the base of the proof of the main results

R2 v1 2026-06-23T11:20:05.184Z