Most of the Open Logic textbooks have seen lots of changes from the versions currently available in hardcopy, so it’s time to refresh those to Fall 2025 editions. These will incorporate all the corrections reported by readers since at least 2023 and in many cases going back to 2020 or earlier.
- Sets, Logic, Computation is seeing the least changes; basically just minor corrections.
- Incompleteness and Computability gets a new chapter specifically on “computability and incompleteness”, i.e., a proof of the first incompleteness theorem via the halting problem. Also added summaries to chapters where they were missing, and lots of smaller corrections and improvements.
- Boxes and Diamonds gets a new section on sequent calculus for modal logics, and two new chapters on temporal and epistemic logic. (Those were originally included in What If?, and the material has now migrated to the main OLP repository.)
- forall x: Calgary will also be updated: no major changes but lots of little things fixed.