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I hope this is the correct forum. If not, please let me know.

I am writing a master thesis in maths and I am not sure, when I do use upright letters for a variable.

Let's have a look at the following sentence: Let $a,m$ be naturals and let $\operatorname{g} := \operatorname{lcm}(a,m)$.

My guess is that I write $a$ and $m$ in cursive, because I can choose them arbitrarily. But I would write $\operatorname{g}$ upright, because it is dependent on $a$ and $b$. In addition, $\operatorname{lcm}$ is an operator, so I write that upright anyways. That's why I would write the $\operatorname{g}$ upright, too.

Is that correct? Is there a style convention?

Lereu
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    If you're going to publish, the style convention will be up to wherever you're actually publishing. I think you should ask them what their guidelines are. – Arthur Jan 10 '24 at 11:01
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    In my opinion (it might be wrong), $g$ should be cursive too. I would only write upright in cases like $\mathrm e$ when it is the constant number or the exponential function, $\mathrm d$ for the derivative operator, etc. (and even these things are commonly written in cursive). – Miguel Mars Jan 10 '24 at 11:09
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    You can use any font you like in your thesis if it is consistent. If you want to write $g$ in cursive, upright, or in any other font is up to you. – stange Jan 10 '24 at 11:12
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    Also, another example of a similar case, we usually write $f(x) = \sin (x)$ with a cursive $f$. – Miguel Mars Jan 10 '24 at 12:07

1 Answers1

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In any style convention I ever was aware of you would write $g$ in your example cursive.

The letters $\operatorname{lcm}$ are upright as a multi-letter operator name.

In fact, in your source code you have written

$\operatorname{g} := \operatorname{lcm}(a,m)$

You would normally just write

$g := \operatorname{lcm}(a,m)$

So, if you are using LaTeX for your thesis, the question is more or less handled automatically, if you put all your math into $...$ and use \operatorname when needed.

Reiner Martin
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  • Thank you. I can understand, but I can't follow the logic, since I abbreviate an upright operator (lcm) with a cursive letter (g). So I have to get used to this style, but at least I have a good opinion from you. Thanks for that! – Lereu Jan 10 '24 at 11:08
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    I would look at it as follows: $g$ is not the operator, but the result of the operator applied to some variables, and therefore a variable itself. – Reiner Martin Jan 10 '24 at 11:11
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    Is your thesis in math or computer science, btw? Maybe there are different conventions in CS. – Reiner Martin Jan 10 '24 at 11:12
  • In math. I will add this information in the post. – Lereu Jan 10 '24 at 11:14
  • BTW, a good reference for style questions is https://www.ams.org/arc/styleguide/mit-2.pdf – Reiner Martin Jan 10 '24 at 11:15
  • Wow, thank you! I will have a look at that! And thanks for your comment "g is not the operator". This was very helpful! – Lereu Jan 10 '24 at 11:15