| Fri, 02 Apr 2021 12:24:29 +0100 | paulson | Cosmetic: no !! in the lemma statement | file | diff | annotate |
| Mon, 13 Jul 2020 17:08:45 +0200 | wenzelm | clarified examples; | file | diff | annotate |
| Tue, 09 Jun 2020 12:13:15 +0100 | paulson | New Ackermann development | file | diff | annotate |