Lemma 17.29.5. Let $f : X \to Y$ be a morphism of ringed spaces. The differentials $\text{d} : \Omega ^ i_{X/Y} \to \Omega ^{i + 1}_{X/Y}$ are differential operators of order $1$ on $X/Y$.

Proof. Immediate from Lemma 17.29.3 and the definition. $\square$

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