Bourbaki

Corollary

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

General Topology, chapter IV, § 7. Infinite sums and products of real numbers

Let (xi)i∈I(x_i)_{i \in I} be a summable family of finite numbers ≥0\geq 0 in R\mathbf{R}. If HH is any subset of II, we have

∑i∈Hxi≤∑i∈Ixi, \sum_{i \in H} x_i \leq \sum_{i \in I} x_i,
and equality holds only if xi=0x_i = 0 for all i∈∁Hi \in \complement H.

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

Cited by

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Cites

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Transcribed from the printed volume. Not translated.