Major errors and corrections

Here's a list of errors on this blog that I think were fairly serious. While what I think of as serious is, of course, subjective, I don't think there's any reasonable way to avoid that because, e.g., I make a huge number of typos, so many that the majority of acknowledgements on many posts are for people who e-mailed or DM'ed me typo fixes. A list that included everything, including typos would both be uninteresting for other people to read as well as high overhead for me, which is why I've dra...