Dear Groffers My tutorial on writing logic with groff is on github
https://github.com/siglun/logic-and-groff I have solved the problems I had with the special logical characters ⊢ (AKA syntactic consequence, turnstile) and ⊨ (AKA semantic consequence, double turnstile). Thanks to everyone who helped me. The solution proposed here on the list was to find a font containing them. Such fonts are available among the Scientific and Technical Information Exchange (STIX) fonts in this project. (I use the STIX font family now). https://www.stixfonts.org/ I'm still polishing the document, adding stuff and removing other stuff (and vice versa). Yours Sigfrid On Tue, 30 Sept 2025 at 19:29, Sigfrid Lundberg <[email protected]> wrote: > I've spent some time writing a tutorial on how to write logic and > natural deductions using groff and eqn. I've also written a handful of pic > and eqn macros for natural deduction. > > https://github.com/siglun/logic-and-groff/blob/main/logic-with-groff.pdf > > Any comments are welcome. > > I've also found some problems when it comes to characters used in logic, > and I do need help on how to implement those. They are > > U+22A2 ⊢ syntactic consequence AKA turnstile > U+22A8 ⊨ semantic consequence AKA double turnstile > > Any pointers as to how to add odd niche characters to what is used by eqn? > > Yours > > Sigfrid > > -- > Sigfrid Lundberg, Ph.D., System developer > Lund, Sweden > https://sigfrid-lundberg.se/ <http://sigfrid-lundberg.se/> > -- Sigfrid Lundberg, Ph.D., System developer Lund, Sweden https://sigfrid-lundberg.se/ <http://sigfrid-lundberg.se/>
