# MathJax is breaking in short expressions frequently today.

Formerly MathJax in comments broke if you had too many consecutive non-blank spaces, and too many was a moderately large number. When it breaks, you see MathJax code in red letters rather than the intended rendered notation.

But today it's been breaking in that way very frequently in short expressions. Can that get fixed?

• E.g., I just suffered from this with $|f(x)-f(a)|=0<\epsilon$ in a comment (and I see it happens here again: Seem a space is introduced in the middle of epsilon – Hagen von Eitzen Aug 16 '16 at 15:50
• Testing $|f(x)-f(a)|=0<\upsilon$. And also Testing $|f(x)-f(a)|=0<\delta$ – davidlowryduda Aug 16 '16 at 15:52
• @mixedmath Are you experimenting with redundant white space? – Hagen von Eitzen Aug 16 '16 at 15:52
• @HagenvonEitzen I was. I'm not quite sure what's up. But that it want to add a space exactly 4 characters into epsilon or upsilon and whatnot is a bit odd. – davidlowryduda Aug 16 '16 at 15:53
• @mixedmath That's twenty characters without space (including the opening $). Used to be eighty. – Daniel Fischer Aug 16 '16 at 16:03 • @DanielFischer I'm a bit surprised that$\alpha\beta\gamma\delta\epsilon\zeta\eta\theta\iota\kappa\lambda$renders fine. Oh! It doesn't! (I lied --- I thought I'd just tested that) Indeed, 20 characters seems to be a new thing. – davidlowryduda Aug 16 '16 at 16:04 • If I guessed right and this has the same cause, things should be fixed (in code, not sure when the next build is rolled out, may take a bit). – Daniel Fischer Aug 16 '16 at 18:35 • Also, it doesn't seem to be just the break of commands, but fractions also don't center properly. More details here: meta.math.stackexchange.com/questions/24839/… (10k only, I deleted it when I realized ~3 minutes after posting that it was a dupe (oops...)) – wythagoras Aug 16 '16 at 19:31 • Test: \frac{\partial}{\partial x}:$\frac{\partial}{\partial x}$. \frac{\partial}{\par‌​tial\theta}:$\frac{\partial}{\par‌​tial\theta}$. – Michael Hardy Aug 16 '16 at 19:39 • When I wrote \frac{\partial}{\par‌​tial\theta} once today, the denominator looked fine but the numerator had$\text{“} {\partial} \text{''}$off to the extreme left (but still above the horizontal bar).$\qquad$– Michael Hardy Aug 16 '16 at 19:41 • @MichaelHardy I had it the other way around here: math.stackexchange.com/questions/1894301/…, where the numerator was fine but the denominator is off to the left, but still below the horizontal bar. – wythagoras Aug 16 '16 at 19:45 • @MichaelHardy$\frac{\partial}{\partial\theta}$vs.$\frac∂{∂\theta}$(\frac∂{∂\theta}) – EKons Aug 28 '16 at 12:51 ## 1 Answer A quick note. We know what's going on, it's a change which had some side effects. I'll take a stab very soon. Update: It looks better now, as you need 60 consecutive unbroken characters to replicate instead of 20. However, it's not finished. Tomorrow I'll simply disable the line breaking shenanigans for comments that have MathJax in them. Update: this is now fixed. Comments which contain mathjax do not receive separators. • So you wrote this stub about the stab. Nice. :P – Asaf Karagila Aug 17 '16 at 20:40 • In case it might be relevant, today I had a comment in which a whitespace mysteriously appeared in the middle of a \equiv. (i.e. it split the word). The problem disappeared after an edit. Very strange. – Bill Dubuque Aug 17 '16 at 21:26 • @MichaelHardy's comment with a \partial in a fraction still seems to have an issue. – LSpice Aug 18 '16 at 16:37 • @LSpice this just came up in chat too A possible explanation is that in that comment the (non-visible) separator was included explicitly in the actual source of the comment (likely inadvertently via a copy paste) as opposed to being automatically inserted on rendering (which is now prevented). – quid Aug 18 '16 at 16:43 • @LSpice sorry for yet another comment but it just occurred to me how to test it. Copy the uncompiled \par‌​tial from that comment that does not render well (that is the last one) and use it by pasting it. This one will always break. But typing it out there will be no problem. $\par‌​tial\par‌​tial\par‌​tial\partial$$\par‌​tial\par‌​tial\par‌​tial\partial$(First three break.) Likely some editors could also show the character, but I don't have one handy (and/or do not know how to do it). – quid Aug 18 '16 at 16:51 • @quid, I can't figure out how to make Firefox display them, but pasting into vim with :set list indeed shows $\par<200c><200b>tial$ for the first 3 and plain ol' $\partial for the last. Thanks! – LSpice Aug 18 '16 at 16:59
• @LSpice. MichaelHardy's comment has some invisible characters embedded in the source. The rendering is perfect. – Sklivvz Aug 18 '16 at 17:00
• Indeed, @quid pointed that out above. Thanks! – LSpice Aug 18 '16 at 17:23