# Period in a wrong position when Mathjax is viewed on iPhone

In the last sentence, after the last aSb, I see a period when viewed on the standard browser of an iPhone SE (but not in Firefox on Linux):

According to the source code, there should be no period there. Bug? Could I ask the mods to ask the SE developers to fix this?

EDIT: It turns out that this is the period terminating the sentence. For whatever reason, it is rendered misplaced. If you remove the period terminating the sentence, the problem disappears.

• edited 5 minutes prior to this question by you. – user645636 Jan 21 at 11:29
• @RoddyMacPhee Right. I tried to get rid of the phantom period before posting here, but failed. – Just_A_Man Jan 21 at 13:35
• line wrapping on mobile possibly. single dollar signs may wrap on mobile so it should be all on one line ending in the prriod but it isn't always. – user645636 Jan 21 at 13:59
• @RoddyMacPhee Possibly. Could I ask the mods to ask the SE developers to fix this? – Just_A_Man Jan 21 at 14:08
• developers are probably too lazy or not site specific. – user645636 Jan 21 at 14:12
• @RoddyMacPhee Let them speak for themselves and let us hope for the best. – Just_A_Man Jan 21 at 14:17
• Probably some of the tags (mobile-web), (ios-app) should be added - depending on where this problem manifests. – Martin Sleziak Jan 21 at 14:47
• @MartinSleziak Done. The problem appears in the standard iPhone Web browser. – Just_A_Man Jan 21 at 14:55
• This bug report on Meta Stack Exchange seems somewhat similar: Strange MathJax line break behavior in mobile browsers. (It also has a MathJax formula broken into two lines and the text seems to follow the first line.) It is from 2015, which does not sound too optimistic. – Martin Sleziak Jan 21 at 18:00
• @MartinSleziak Let's hope that as you linked this bug report there, the chances increased. (I have no reputation there on meta, so, I cannot upvote there, though I'd like to.) – Just_A_Man Jan 21 at 18:14
• The period will appear property if you enclose it within the dollars. – Shivering Soldier Jan 22 at 2:18
• @ThomasShelby Wow, that’s a kludge. Semantically, a period terminates a sentence, not a formula. Anyway, good to know, thanks !!! – Just_A_Man Jan 22 at 5:06

Testing: Does the phantom period appear if I simplify it to this? $$\forall\,a,b\in\pi_1(S)\cup \pi_2(S)\colon aSb\Leftrightarrow f(a) S' f(b)$$.
Yes. In this screen grab, see the period after $$aSb$$, but the period after $$f(a) S' f(b)$$ is missing.