Hello,

I'm currently working on a problem in Polygon, and I have an issue with rendering mathematical expressions. The expression renders normally on Polygon HTML and PDF, but on Codeforces it just shows as an image that can't be loaded. At first I thought I made a mistake, but the same thing happens with an example from Polygon page.

This is the example I'm trying to render:

Some complex formula:

This is what renders on Polygon HTML page:

And this is what renders on Codeforces:

My guess is that the problem is somehow related to the limits of the sum, because formulas without them render normally. I would like some help :)

Also, I've seen that a recent problem has successfully used a sum in a formula — 1614D2 - Divan and Kostomuksha (hard version), so I guess it can be done somehow.

Hello, in February I reached Expert title and in the sidebar I got a "Propose a problem/contest" button. On the next contest, I lost the Expert title and the button disappeared as well. I regained the title about 10 days ago, but the button never reappeared, so I'm wondering is it a bug, did the rules about problemsetting change in the meantime, or something else happened? I have read the FAQ blog post and it states that Experts need to have participated in at least 25 rated contests to propose problems, which I have, so I really don't understand what's the problem.

Thanks in advance.