# How do you tag without brackets? In particular, how do you tag boxes?

How would you tag boxes without brackets after completing a proof? For example, I needed to prove that $$\forall m, n \in \mathbb{N}\cup \{0\}, \ n^{2m + 1} \equiv -1 \pmod {n + 1}$$ I proved this by showing that $$n^{2m + 1} + 1 = n^{2m + 1} - (-1) = n^{2m + 1} - (-1)^{2m + 1}$$ And since $$a^k - b^k = (a - b)\sum_{i = 1}^k a^{k - i}b^{i - 1}$$ then this meant $$n + 1 \mid n^{2m + 1} + 1$$ or $$n^{2m + 1} \equiv -1 \pmod {n + 1}$$ In the event that I want to draft up a proof using LATEX, how would I tag a box $\Box$ to show that I have demonstrated the proof without it having brackets like $(\Box)$? Namely, if I had a Statement $A$ then I don’t want it looking like $$\text{Statement A}\tag{\Box}$$ and if I use \quad and/or \qquad then it looks like $$\text{Statement A}\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\quad \ \ \ \ \Box$$ Thank you in advance.

• @MartinSleziak thanks for the edit :) Jan 16, 2018 at 6:54

EDIT: I agree with what mixedmath says in their answer that this is not a reasonable thing to do in order to mark the end of a proof. I read your question simply as a TeX-nical (or MathJax-nical) question: "How do I mark equation with $\Box$ rather than $(\Box)$ on the right?"

Probably the intended question is related to possibilities how to mark end of proof (in a way similar to \qed in LaTeX), which is question related to style of writing and MathJax. (And which means that I have misunderstood your question.) Probably you might have a look at past discussion here: \qed for MathJax here on stackexchange.

If you do not net MathJax markup in the tag you can do this simply using \tag*. Compare the following two equations: $$a^2+b^2=c^2 \tag{1}$$ $$a^2+b^2=c^2 \tag{1}$$ and $$a^2+b^2=c^2 \tag*{1}$$ $$a^2+b^2=c^2 \tag*{1}$$

It is slightly complicated if you want some mathematical formula as a part of the tag, see also here: I can't put a Greek letter into \tag{…}

You can do this $$a^2+b^2=c^2 \tag{\Box}$$ $$a^2+b^2=c^2 \tag{\Box}$$ and also this $$a^2+b^2=c^2 \tag*{\Box}$$ $$a^2+b^2=c^2 \tag*{\Box}.$$

I would typically expect you to include a box inline, such as this. $\square$

An indication that you are trying to do something in a way that isn't how it is designed is that you are trying to use tag to produce something other than a tag or label.

If you really want to shove a square to the far right, I only know how to do this (with mathjax) in a multline environment, as below.

$$\begin{multline} \shoveright \square \end{multline}$$

But I would suggest that you never do this.

• Interestingly, using \tag* is one of the suggested solutions in the previous discussion about this. I will leave to others to judge whether this is good style or not. (Personally I consider the advice from your answer very reasonable.) Jan 16, 2018 at 7:15

I mostly separate sections on this site with

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

which usually comes out matching the width of my answer window. My idea is that people can't read this site as carefully as a book they are holding in their hands, something that crosses the window gives a more reliable notice that something different is starting. if you want to say QED before that, fine.

• I will add that it is also possible to use simply <hr> or ---. (In which case you do not have to worry about the length, the SE software does that for you.) For other possibilities, see the section on horizontal rules in editing help. Jan 17, 2018 at 6:29
• It might match the width of your answer window, but other people might be viewing in a phone browser or with different fonts installed on their computers. --- is much more consistent. Jan 18, 2018 at 14:58