Lemma 22.35.5. Let (\mathcal{C}, \mathcal{O}) be a ringed site. Let K^\bullet be a complex of \mathcal{O}-modules. Then the functor
of Lemma 22.35.3 is a left adjoint of the functor
of Lemma 22.32.1.
Lemma 22.35.5. Let (\mathcal{C}, \mathcal{O}) be a ringed site. Let K^\bullet be a complex of \mathcal{O}-modules. Then the functor
of Lemma 22.35.3 is a left adjoint of the functor
of Lemma 22.32.1.
Proof. The statement means that we have
bifunctorially in M and L^\bullet . To see this we may replace M by a differential graded E-module P with property (P). We also may replace L^\bullet by a K-injective complex of \mathcal{O}-modules I^\bullet . The computation of the derived functors given in the lemmas referenced in the statement combined with Lemma 22.22.3 translates the above into
where \mathcal{B} = \text{Comp}^{dg}(\mathcal{O}). There is an evaluation map from right to left functorial in P and I^\bullet (details omitted). Choose a filtration F_\bullet on P as in the definition of property (P). By Lemma 22.20.1 and the fact that both sides of the equation are homological functors in P on K(\text{Mod}_{(E, \text{d})}) we reduce to the case where P is replaced by the differential graded E-module \bigoplus F_ iP. Since both sides turn direct sums in the variable P into direct products we reduce to the case where P is one of the differential graded E-modules F_ iP. Since each F_ iP has a finite filtration (given by admissible monomorphisms) whose graded pieces are graded projective E-modules we reduce to the case where P is a graded projective E-module. In this case we clearly have
as graded \mathbf{Z}-modules (because this statement reduces to the case P = E[k] where it is obvious). As the isomorphism is compatible with differentials we conclude. \square
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