# Circumventing displayed equation ban in titles

Using block equations in titles is dissallowed and will be automatically caught. But one can circumvent this ban by using

$$insert-equation-here$$

This was the case in this question (see revision 2).
It seems that one can also use $...$, \begin{align} and \begin{cases} to achieve same undesirable effect.

Can we also have a ban on these commands from titles?

You can also circumvent it with \begin{align}. Or with \displaystyle. Or put \dfrac inside \dfrac inside \dfrac. Or put a huge matrix into a title: it can be {matrix}, {pmatrix}, {vmatrix}, or {bmatrix}. Or a {cases} statement. Or use explicit size modifiers like \Huge.

My point is, there are many ways to make a poorly formatted title. (And that's only talking about the size... imagine bright red titles made with {color}). Software checks for the most common of them, with the purpose of catching a typical mistake made by people unaware that titles have limited vertical space in the layout. If someone wants to be obnoxious, software will never be able to stop them. That's up to the users.

• displaystyle and dfrac=display fraction are discouraged already meta.math.stackexchange.com/questions/9687/… – dustin Jan 3 '15 at 15:30
• @dustin yes, but the question proposes an automatic check against it. – quid Jan 3 '15 at 15:45
• @quid I agree there should be a block on it. – dustin Jan 3 '15 at 15:48
• But align, dfrac, displaystyle, etc., at least doesn't generate math in new line. – jdoicj Jan 3 '15 at 16:09
• @HatMan align does, it can even generate multiple new lines. – user147263 Jan 3 '15 at 16:10
• Err. I now realize it. I will edit the question to include other problematic commands and see what SE staff has to say. – jdoicj Jan 3 '15 at 16:18
• @HatMan I'm not SE staff, but I can guess what they'd have to say: "is this a problem that actually demands developer time put into it"? How often do users put or \begin{align} in titles? – user147263 Jan 3 '15 at 16:21
• Any way, I gave it a try. – jdoicj Jan 3 '15 at 16:32
• I've often said that it's best not to try to use technology to solve people problems. – Todd Wilcox Jan 7 '15 at 22:39

Since most user don't bother to read meta, paying attention to what is being edited, or just plan ignore it, it would be nice if those LaTeX formats would be banned from the title all together. By banned, I mean that the post will not post if one of the offending formats is in the title.

From just the small list, we can see that over the years this problem has continued and seems not to be improving since

1. some members are editing post by editing disallowed formats
2. there is only a small group of people who re-edit those titles
3. new users may not know better

I don't know a way to check if this works in a title without breaking the rules myself, but I suspect it is possible to spam copies of \\ \, in math mode to generate a lot of lines, like this: $a \\ \, \\ \, \\ \, \\ \, \\ \, \\ \, \\ b$