forall x: Calgary goes international (and other updates)

ICYMI, forall x: Calgary has been translated into German and Portuguese! forall x: Dortmund by Simon Wimmer is the German version (PDF) and para todxs: Natal by Daniel Durante et al is the Portuguese version. If I understand correctly, they are looking for help in revising the final version of the translation.

In other news, I’ve started working on the Fall 2021 version of forall x: Calgary. There won’t be any drastic changes. So far I’ve added a section on “only” and “except” and revised the material on interpretations in FOL a little bit. I’m hoping to have another chapter on chains of equivalences (to transform sentences into CNFs and DNFs).

This means that the PDFs at the download site have already changed quite a bit. In case you rely on that site for student access to the textbook, I have provided links to the most current version of the Fall 2020 edition. (The links have changed, too, so you may want to update them.) You can see a list of all the changes between the Fall 2020 version and the current version here. If you have corrections or suggestions for improvements, now is the time to open an issue or to just send me an email.

I’ve now been using Graham Leach-Krouse’s Carnap online logic software for two years with great success. It supports forall x: Calgary almost completely (only exercises for modal logic are not supported). You can read my (by now old-ish) post on how to add automatically graded exercises to your logic course using Carnap here; it links to some practice exercises on Carnap to go along with forall x: Calgary. The older proof editor due to Kevin Klement is still online at, although that still uses the pre-2019 syntax for FOL. That proof checker has also be translated into Portuguese.