TITLE: What is the crime of lèse-Bourbaki?
QUESTION [55 upvotes]: In the foreword to his textbook Algebra, Serge Lang writes (on page vi)

I have frequently committed the crime of lèse-Bourbaki by repeating short arguments or definitions to make certain sections or chapters logically independent of each other.

What does "the crime of lèse-Bourbaki" mean? I do not understand French, so naturally I googled the phrase and what turned up was the Wikipedia page for lèse-majesté.

Lèse-majesté is the crime of violating majesty, an offence against the dignity of the reigning sovereign or against a state.

I am aware that Nicolas Bourbaki is a pseudonym used by a group of influential French mathematicians who wrote a series of textbooks in a terse and formal manner. So, is Lang honoring Bourbaki by equating them with (mathematical) royalty?

REPLY [7 votes]: This is not really an answer to the stated question, which the other answers address in a quite satisfactory manner, but I would like to point out that Lang somewhat misleadingly describes the Bourbakist principle of economy. Not only should one not repeat definitions or arguments identically, one should more generally not explicitly prove any result (say about vector spaces) if it can be seen as a special case of a result valid in a more general context (say of modules over a not necessarily commutative ring). In that case it should instead just be recalled that the more general result, necessarily appearing at some earlier point due to the "the from general to the specific" ordering of the Bourbaki oeuvre, has a certain implication in the current (more specific) setting.