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The Stacks project

Lemma 96.19.9. Let f : \mathcal{U} \to \mathcal{X} be a 1-morphism of categories fibred in groupoids over (\mathit{Sch}/S)_{fppf}. Let \tau \in \{ Zar, {\acute{e}tale}, smooth, syntomic, fppf\} . Assume

  1. \mathcal{F} is an object of \textit{Mod}(\mathcal{X}_\tau , \mathcal{O}_\mathcal {X}),

  2. for every object x of \mathcal{X} there exists a covering \{ x_ i \to x\} in \mathcal{X}_\tau such that each x_ i is isomorphic to f(u_ i) for some object u_ i of \mathcal{U},

  3. the category \mathcal{U} has equalizers, and

  4. the functor f is faithful.

Then there is a first quadrant spectral sequence of \Gamma (\mathcal{O}_\mathcal {X})-modules

E_1^{p, q} = H^ q((\mathcal{U}_ p)_\tau , f_ p^*\mathcal{F}) \Rightarrow H^{p + q}(\mathcal{X}_\tau , \mathcal{F})

converging to the cohomology of \mathcal{F} in the \tau -topology.

Proof. The proof of this lemma is identical to the proof of Lemma 96.19.8 except that it uses an injective resolution in \textit{Mod}(\mathcal{X}_\tau , \mathcal{O}_\mathcal {X}) and it uses Lemma 96.17.6 instead of Lemma 96.17.5. \square


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