Remark 2

Tag 0AUX, permanent. Cite it as [Bourbaki, Tag 0AUX].

Lie Groups and Lie Algebras, chapter VI, § 1. Root systems

If $x, y \in C$ , then $(x|y) > 0$ (Chap. V, § 3, no. 5, Lemma 6), in other words the angle $(x, y)$ is acute.

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

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Nothing.