The discussion revolves around the meaning of the abbreviation "Ad" as used in Eberhard Zeidler's book "QFT: Basics in Mathematics and Physics." Participants explore its significance within the context of proofs presented in the text.
Participants express various interpretations of "Ad," with some suggesting it relates to "adjoint" and others proposing it means "Ad hoc." There is no consensus on its definitive meaning, and the discussion remains unresolved.
Some participants note the lack of specific examples from the text, which may limit the ability to reach a clear understanding of the abbreviation's usage.
Since you don't give an example and most people will not have that book available, I think many will be able to answer this. Since this is posted under "Quantum Physics", and linear operators are often used there, without any more information I would suspect something line "adjoint" as in "ad T" is the adjoint of the operator T. Was "ad" used with an operator or just as a word on its own?Jimmy Snyder said:I'm reading QFT: Basics in Mathematics and Physics, by Eberhard Zeidler. Once in a while, in his proofs, I see the word (abbreviation?) Ad. For instance on page 375. The author is German and I suppose this imight be common practice in German texts. Does anyone here know what it means?
I'm sorry, I didn't realize that there were some people that don't have a copy of the book. It must stand for some kind of enumeration like case N, case R, etc. That's how it is used on page 375.my_wan said:I've seen it used as the prefix for an enumeration of the steps in a proof, but don't know what it stands for.
Thanks unusualname.unusualname said:It's an abbreviation for "Ad hoc" which means "for this" (case) as you guessed.