Bourbaki

Proposition 12

Tag 06XJ, permanent. Cite it as [Bourbaki, Tag 06XJ].

Algebra, chapter VI, § 1. Ordered groups. Divisibility

— Let xix_i (1≤i≤n1 \leq i \leq n) be n pairwise coprime elements in a lattice ordered group. Then

sup⁡(x1,…,xn)=x1+⋯+xn. \sup(x_1, \ldots, x_n) = x_1 + \cdots + x_n .

This follows from the formula u+v=sup⁡(u,v)+inf⁡(u,v)u + v = \sup(u, v) + \inf(u, v) (VI, p. 10, Prop. 7) by induction on nn, using the fact that xix_i is coprime to x1+…+xi−1x_1 + \ldots + x_{i-1} for 2≤i≤n2 \leq i \leq n (Cor. 4 to Prop. 11).

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

Cited by

Nothing.

Cites

Transcribed from the printed edition, 2003, Springer. Not translated.