Link: AMS Open Math Notes
AMS recently launched a repository of mathematics lecture notes / textbook drafts.
This might be a great improvement over the current practice of every lecturer hosting their notes on their uni web pages. If I find a great set of lecture notes and link to them, those links will, eventually, die. (There exists a popular conjecture: 90% of HTML links in any given printed material 404’s or point to outright dead or disappeared webservers.) So as a precaution, I download every and all maths pdfs I read, just to be sure it won’t disappear: but what I should do if I want to redistribute them later, or refer to them?
With papers and pre-prints the answer is easy: I store Arxiv link and possibly a DOI. If this AMS repository gets popular, I can imagine it serving as an “Arxiv of open textbooks” of sorts.