I learned Pascal, programming logic based on invariants, WP, ... and algorithms with Pierre-Arnoul de Marneffe between 1994 and 1998. That was a very good time

I learned Pascal, programming logic based on invariants, WP, ... and algorithms with Pierre-Arnoul de Marneffe between 1994 and 1998. That was a very good time and proved so interesting and useful. I knew he had someting to do with Knuth and Oberon.