Should one really write $\text{det}A$, instead of $detA$, similarly $\text{Aut}G$ instead of $AutG$, or is $det$, $Aut$ acceptable?

• I would use \operatorname{det}(A), as that's what it is. – gnometorule Feb 1 '13 at 4:51
• Welcome to TeX.sx! Your post was migrated here from Math.SE. Please register on this site, too, and make sure that both accounts are associated with each other (by using the same OpenID), otherwise you won't be able to comment on or accept answers or edit your question. – Werner Feb 1 '13 at 6:19

Note that $det(A)$ simply looks like it might mean $d\cdot e\cdot t(A)$. With respect to correct spacing in context, \operatorname is definitely the way to go.

• Better note that \det is predefined in LaTeX, so $\det(A)$ will give the correct result out of the box. – egreg Feb 1 '13 at 9:52
• @egreg Yes, \operatorname is rather for the generic case (such as Aut in the OP). – Hagen von Eitzen Feb 1 '13 at 13:40
1. $\det A$

2. $\text{det}A$

3. $\mathrm{det}A$

4. $\operatorname{det}A$

Personally, I prefer the first option or fourth option, as without italicization, it distinguishes the "operator" from the operand (matrix $A$ in this case), and/or from other variables, which are italicized.

And the advantage of the first and last option is the slight increase in spacing between the operator (\det) or (\operatorname{det}) and the operand, $A$.

See Deven's suggestion in the comment below: if you plan to use the "operator" a lot in a given post, you can write a "preamble" defining a "new command", which helps economize the effort involved in formulating a long post.

• \text should generally not be used: it uses the font of the surrounding text, which might be italic or small caps... It should be reserved for words that are part of the text. – Mariano Suárez-Álvarez Feb 1 '13 at 6:12
• As for defining operators, there is a standard \DeclareMathOperator command in amslatex.sty. – Mariano Suárez-Álvarez Feb 1 '13 at 6:13
• \operatorname not only increases the spacing when it is needed, it also removed the space when the next thing is a delimiter (like parentheses) and has a couple of other technical niceties that make it the correct option. – Mariano Suárez-Álvarez Feb 1 '13 at 6:15
• There already is \det, no need to define it yourself. – morbusg Feb 1 '13 at 6:35
• For things that are operators \DeclareMathOperator or \operatorname is the way to go, for example $\mathrm{sin}\theta$ just looks wrong. On the other hand, one might argue that things that are just names for sets, could just be written as \mathrm{Mat}(R,n) (obviously I'd make a \Mat macro), because it would not be used in a context where something could be seen as multiplication. \text` should never be used to get something appear in upright, as it will be italic in an italic context. – daleif Feb 1 '13 at 9:11