Lemma 15.97.2. Let $A$ be a ring and $I \subset A$ an ideal. Suppose given $K_ n \in D(A/I^ n)$ and maps $K_{n + 1} \to K_ n$ in $D(A/I^{n + 1})$. Assume
$A$ is $I$-adically complete,
$K_1$ is pseudo-coherent, and
the maps induce isomorphisms $K_{n + 1} \otimes _{A/I^{n + 1}}^\mathbf {L} A/I^ n \to K_ n$.
Then $K = R\mathop{\mathrm{lim}}\nolimits K_ n$ is a pseudo-coherent, derived complete object of $D(A)$ and $K \otimes _ A^\mathbf {L} A/I^ n \to K_ n$ is an isomorphism for all $n$.
Proof. We already know that $K$ is pseudo-coherent and that $K \otimes _ A^\mathbf {L} A/I^ n \to K_ n$ is an isomorphism for all $n$, see Lemma 15.97.1. Finally, $K$ is derived complete by Lemma 15.91.14. $\square$
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