Reminds me of this beautiful 1964 paper by Janus Brzozowski where he applies differential calculus rules symbolically to regular expressions to derive a recogni

Reminds me of this beautiful 1964 paper by Janus Brzozowski where he applies differential calculus rules symbolically to regular expressions to derive a recogniser for it. https://dl.acm.org/doi/pdf/10.1145/321239.321249 https://dl.acm.org/doi/pdf/10.1145/321239.321249