How do the science and math papers use characters that aren't in... ASCII? Maybe I need to look at an ASCII chart. Out of curiosity, isn't UTF implementation m

How do the science and math papers use characters that aren't in... ASCII? Maybe I need to look at an ASCII chart. Out of curiosity, isn't UTF implementation much easier now than it has been? I piddle in writing things and I rarely contemplate UTF. Once I tried to reverse engineer an encryption plugin that used Asiatic characters as the ciphertext, and I wanted to use emoji, and that was when I learned I am too dumb to understand utf. But there's libiconv, which I first saw in production (ICQ or aim or Trillian or so) over 22 years ago, personally. So is the latex thing obstinance, technical, or political?