# What does this symbol mean and how do you type it in LaTeX?

#### Ragnarok

##### Member
I'm reading Georgi Shilov's Linear Algebra and at the bottom of page 10 is has an equation $$\displaystyle a_{ij}=\lambda b_i+\mu c_i +\ldots +\tau ?_i$$
Where the ? is there is a symbol that I don't know. It looks like a curly lowercase f (like an integral symbol with a short stroke through the top part). It looks kind of like this:

But not completely. The dash is not slanted and it is shorter and more towards the top. Sorry if this is an obvious symbol! If anyone knows what I'm talking about could you tell me what it is used for and how you could write it in LaTeX? Thanks!

#### Sudharaka

##### Well-known member
MHB Math Helper
I'm reading Georgi Shilov's Linear Algebra and at the bottom of page 10 is has an equation $$\displaystyle a_{ij}=\lambda b_i+\mu c_i +\ldots +\tau ?_i$$
Where the ? is there is a symbol that I don't know. It looks like a curly lowercase f (like an integral symbol with a short stroke through the top part). It looks kind of like this:

View attachment 1013
But not completely. The dash is not slanted and it is shorter and more towards the top. Sorry if this is an obvious symbol! If anyone knows what I'm talking about could you tell me what it is used for and how you could write it in LaTeX? Thanks!
Hi Ragnarok,

I guess the symbol might depend on the edition and the publisher of the book in question. I mean, even if members have the book they might see a different symbol than what is in your book because they have a different edition and/or publication. So can you mention the edition and the publisher of the book? Also it would be really helpful if you can include a photo of the equation.

#### Bacterius

##### Well-known member
MHB Math Helper
Well it is presumably a greek symbol, as the equation seems to be using them: $\lambda$, $\mu$, .. Does anything on this page look similar?

In LaTeX there's $\digamma$ but it may be a variant of that, just a wild guess..

#### topsquark

##### Well-known member
MHB Math Helper
$$\displaystyle a_{ij}=\lambda b_i+\mu c_i +\ldots +\tau ?_i$$
Whatever it is it's obviously something in LaTeX code, but my guess as to the given expression is that it's a typo. The last term simply doesn't match with the rest of the equation. It should be some kind of (English) alphabet letter as in the other terms.

-Dan

#### dwsmith

##### Well-known member
I'm reading Georgi Shilov's Linear Algebra and at the bottom of page 10 is has an equation $$\displaystyle a_{ij}=\lambda b_i+\mu c_i +\ldots +\tau ?_i$$
Where the ? is there is a symbol that I don't know. It looks like a curly lowercase f (like an integral symbol with a short stroke through the top part). It looks kind of like this:

View attachment 1013
But not completely. The dash is not slanted and it is shorter and more towards the top. Sorry if this is an obvious symbol! If anyone knows what I'm talking about could you tell me what it is used for and how you could write it in LaTeX? Thanks!
http://www.mathhelpboards.com/f26/need-help-identifying-certain-latex-characters-5223/

At this thread, I have link to site where you can draw the symbol and it will look it up for you.

Since you didn't post a picture of the symbol and just a close example, I have found

\usepackage{ tipa }
\texthtbardotlessj

Last edited:

#### Ragnarok

##### Member
Thanks everyone. I did indeed use the LaTeX symbol-drawing tool to find the \fint symbol which looks similar. I do not believe it is a typo since it also appears on the next page.

I agree that I expected it to be a Latin alphabet letter to be consistent.

#### Ackbach

##### Indicium Physicus
Staff member
$$a_{ij}=\lambda b_{i}+\mu c_{i}+ \dots +\tau f_{i}.$$
\begin{align*}
D_{j}(a_{ij})&=D_{j}(\lambda b_{i}+\mu c_{i}+ \dots +\tau f_{i})\\
&=\lambda D_{j}(b_{i})+\mu D_{j}(c_{i})+ \dots+ \tau D_{j}(f_{i}).
\end{align*}

It's just the normal 'f' character as typed in a math environment.

#### Ragnarok

##### Member
Well, I feel stupid. Thank you!

Any reason why he would have chosen tau and f?

#### topsquark

##### Well-known member
MHB Math Helper
Well, I feel stupid. Thank you!

Any reason why he would have chosen tau and f?
Probably just what the author was used to or convenient letters for later. Personally I would have labeled the last term either with a $$\nu d_i$$ (the next letters after $$\mu$$ and c in Greek and English in the series) or by $$\omega z_i$$ (the last letter of both alphabets.)

And hey, I spent two days trying to figure out what the unit "h" was supposed to represent. I finally got an answer at PhysicsForums (in my pre-MHF and MHB days) and found out it means "hour." Kind of embarrassing, but everyone misses the obvious occasionally.

-Dan