Bourbaki

Example 1

Tag 03VL, permanent. Cite it as [Bourbaki, Tag 03VL].

Theory of Sets, chapter IV, § 2. Morphisms and derived structures

Take Σ\Sigma to be the species of order structures and let σ{x,y,s,t}\sigma\{x,y,s,t\} denote the set of all mappings ff of xx into yy such that the relation (u,v)∈s(u,v)\in s implies (f(u),f(v))∈t(f(u),f(v))\in t. With the notation of Chapter III, § 1, this means that u⩽vu \leqslant v implies f(u)⩽f(v)f(u) \leqslant f(v), i.e., that ff is increasing. The verification of axioms (MOI)(\mathrm{MO_I}), (MOII)(\mathrm{MO_{II}}), and (MOIII)(\mathrm{MO_{III}}) is obvious.

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

Transcribed from the printed edition, 2004, Springer. Not translated.