Add a new "negated syllogism inference" named nsyl5 to main. nsyl5 is to nsyl4 what nsyl is to nsyl3. I encountered the need for such an addition already several times (for example moexexlem,, wl-nax6im, and more), and today again while designing a proof. This time I had enough.
I looked up simple patterns for a possible application, and let the metamath minimizer do the work. I currently count 44 replacements, saving 7 lines in total.