Roman vs. Greek letters for variables

[oneamp]

I am writing a paper and I was using 'o' for a variable. Then I decided that it looked too much like '0', and thought I might use capital omega. How do I know when I should and should not use Greek letters?

Thanks

 

[adjacent]

What kind of paper? Different letters are used for different purposes.

 

[micromass]

In principle, you could use any variable you want. Mathematically, everything is allowed. However, you should consider readibility. For example, using $\pi$ as a variable in equations is probably not the best idea. Or using $x$ as the function symbol and $f$ as variable to get stuff like $x(f) = f^2 + f + 1$ is also something you should want to avoid.

But it really depends on context.

 

[oneamp]

Thank you. So it's arbitrary. Also, is using something like [smth]_{sub}, where sub is subscript, ok to use, or should I push the limit with unrelated (phonetically) roman and greek letters, instead of words with a subscript?

 

[micromass]

Thank you. So it's arbitrary. Also, is using something like [smth]_{sub}, where sub is subscript, ok to use, or should I push the limit with unrelated (phonetically) roman and greek letters, instead of words with a subscript?

Subscripts are perfectly fine. But again, it depends on the context. The end result should be a readable text, so notation shouldn't be confusing. That's the only rule.

 

[oneamp]

Subscripts are perfectly fine. But again, it depends on the context. The end result should be a readable text, so notation shouldn't be confusing. That's the only rule.

I was more curious about using whole words above the subscript. Eg. $var_{now}$; can't $var$ be misinterpreted as three variables? Or is it ok to use it?

Thank you again

 

[micromass]

I was more curious about using whole words above the subscript. Eg. $var_{now}$; can't $var$ be misinterpreted as three variables? Or is it ok to use it?

Thank you again

It should be acceptable, but it's certainly something that you don't see very much.

In any case, use the text environment if you're using this. So

\text{var}_\text{now}

To get $\text{var}_\text{now}$

 

[oneamp]

Thank you

 

[symbolipoint]

Thank you. So it's arbitrary. Also, is using something like [smth]_{sub}, where sub is subscript, ok to use, or should I push the limit with unrelated (phonetically) roman and greek letters, instead of words with a subscript?

Subscripts are perfectly fine. But again, it depends on the context. The end result should be a readable text, so notation shouldn't be confusing. That's the only rule.

We have learned some unofficial conventions. f and sometimes g and h are often used for function names. Certain greek letters are often used as angle measure variables.

One maybe obvious reason for single-character variable names is that we place factors next to each other with the understanding that if no operation symbol is shown, then multiplication is understood. We can not try to spell human-language words with these kinds of variables. Why? Each letter is supposed to be a separate number.

 

[Lavabug]

I've seen both in the literature but Greek letters are always more common, I think Roman letters are more typically used for dimensionless parameters like in numerical simulations or for geometric quantities (x,y,z, L etc.)

Plenty of Greek letters with Roman super/subscripts in papers, though the super/subscripts are almost universally in roman font instead of the default TeX font, something I was told by my senior year project advisor. Ie:

\Omega_{\rm{something}}

 

[Vanadium 50]

It's not arbitrary. This is a form of communication, and you should pick your variable names to facilitate communication. For example, you could say that the area of a circle is $\pi^2 R$, where $\pi$ is the radius of the circle and $R$ is the ratio of a circle's circumference to its diameter. And you'd be technically right. But this would be a very confusing thing to say.

 

[lurflurf]

In principle, you could use any variable you want. Mathematically, everything is allowed. However, you should consider readibility. For example, using $\pi$ as a variable in equations is probably not the best idea. Or using $x$ as the function symbol and $f$ as variable to get stuff like $x(f) = f^2 + f + 1$ is also something you should want to avoid.

But it really depends on context.

Thanks. I am going to start doing that all the time, but I like to use functions and operators that act to the left and no parenthesis so I will write

$f\mathrm{x}=f^2 + f + 1 \\ f^2\mathrm{x}=f^4 + f^2 + 1 \\ \Xi\pi\sin\mathrm{d}=\Xi\pi\mathrm{d}(\Xi\pi\ \cos)=(\Xi \mathrm{d}\pi+\pi\mathrm{d} \Xi)(\Xi\pi\ \cos)$

looks great