I've always been bothered with normal operator ordering, writing `$:O(a)O(b):$`

always produces bad results.

The quick fix I've been using is the following:

\def\normOrd#1{\mathop{:}\nolimits\!#1\!\mathop{:}\nolimits} %% % example: % \begin{equation} % \normOrd{a(z)b(\omega)} = a(z)_{+}b(\omega)+(-1)^{\alpha\beta}b(\omega)a(z)_{-} % \end{equation} %%Which in practice looks like:

## How I got this solution

I determined this solution iteratively after many different attempts, which I shall enumerate along with the problems they each had.However, using mere colons

`:a(z)b(\omega): = ...`

produces the following:Being clever, I asked myself "Hey, why not write

`:x\colon`

for the normal ordering?" This was clever, but wrong. Consider the following example:g = :x\colonProducing:

Not one to give up easily, I found a

`\cocolon`

definition on tex.stackexchange. Trying that instead:g = \cocolon x\colon = yProduces strange extra whitespace on the right:

After examining the co-colon code, I just determined that something along the lines of

% rough draft definition #1 \def\normOrd#1{\mathrel{:}\!#1\!\mathrel{:}}would work. This didn't quite work, the whitespacing was strange. So instead I just use

`\mathop{:}\nolimits...`

, which produces the desired result.
Any chance of resurrecting a post from 2009, where you wrote about latex/emacs macros? It kind-of went way over my head. Would love see a simpler tutorial. For example, is there a way to automate cite command? E.g. first ask me for page number, then for cite key?

ReplyDeleteCheers!

Ah, I should give you the motivation behind that post: I was working with a netbook, and wanted to write up some notes in LaTeX.

DeleteThe problem: the "\" key was too small for me to hit!

The solution: concoct some emacs macros to simplify typing in LaTeX code (e.g., "C-l C-e" for writing "\begin{equation}\n\n\end{equation}").

As far as automating citation, well, I don't know offhand how to do that. But -- knowing Emacs! -- there are probably a million different packages out there...

\DeclarePairedDelimiter{\normalorder}{\vcentcolon}{\vcentcolon} with mathtools deals with it the best way, in my opinion.

ReplyDeleteThanks for sharing these useful information! This is really interesting information for me.

ReplyDelete