Yes, but I think such references are inherently harder to locate. Personally I try to just avoid making references to specific locations in the document and instead name anything that needs to be referenced (e.g. Figure 5, Theorem 3.2).
I generally stick to PDF myself, but I do sometimes wish it would be more ergonomic to reflow a 2-column paper for reading on mobile on the go, for example. Also, ePub is easier to read in night mode than PDF recoloring, and seems easier to search through (try searching for a Greek letter in a PDF…).
EDIT: How is the math support in ePub though? Are people embedding KaTeX/MathJax or just relying on MathML, and how is the quality compared to TeX?
I'm guessing there are few web pages of any significance which need to stay exactly the same for a long time. Here is one example which I've seen trotted out from time to time on HN:
https://www.dolekemp96.org/main.htm
This is clearly the exception. It seems that maintainers of web pages usually expect that they'll need to maintain and update them for as long as they want them to be accessible, and that's definitely not something I'd care to do for research papers.
Just thinking about having to change layout-dependent references, every time I add two sentences to the introduction, gives me a migraine.
I never do anything like this in the paper itself, nor does anyone else that I'm aware of. I'm thinking of informal discussions, where I ask another mathematician about something specific in a paper.
The tooling producing PDF by default absolutely makes the preference for PDF justifiable. However, tooling is driven by usage - if more papers come with rendered HTML (e.g. through Pandoc if necessary), and people start preferring to consume HTML, then tooling support for HTML will improve.
> But also, we tend to prefer that the formatting be semi-canonical, so that "the bottom of page 7" or "three lines after Theorem 1.2" are meaningful things to say and ask questions about.
Couldn't you replace references like "the bottom of page 7" with others like "two sentences after theorem 1.2" that are layout-independent? This would also make it easier to rewrite parts of the paper without having to go back and fix all of your layout-dependent references when the layout shifts.
HTML has strong advantages for both paper and electronic reading, so I think it's worth making an effort to adopt.
When I print out a paper to take notes, the margins are usually too narrow for my note-taking, and I additionally have a preference for a narrow margin on one side and a wide margin on the other (on the same side, not alternating with page parity like a book), which virtually no paper has in its PDF representation. When I read a paper electronically, I want to eliminate pagination and read the entire thing as a single long page. Both of these things are significantly easier to do with HTML than LaTeX (and, in the case of the "eliminate pagination" case, I've never found a way to do it with LaTeX at all).
(also, in general, HTML is just far more flexible and accessible than PDF for most people to modify to suit their preferences - I think most on HN would agree with that)