Thanks. I updated set.mm with your shorter proof, which you can see at http://us2.metamath.org/mpeuni/mmrecent.html#thlist BTW "bi2" was renamed "biimpr" (for better naming consistency) on Aug. 7.
Norm On Monday, August 17, 2020 at 3:09:40 AM UTC-4, roger witte wrote: > > I was just browsing and noticed that the published proof of bianir has has > two redundant commutations of logical equivalence. The shorter proof goes > > 1. bi2 .. ⊢ ((ψ ↔ φ) → (φ → ψ)) > 2. impcom .1. ⊢ ((φ ∧ (ψ ↔ φ)) → ψ) > > Regards > Roger > -- You received this message because you are subscribed to the Google Groups "Metamath" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/metamath/a93f38f5-0516-4066-8117-0f079ebf0e41o%40googlegroups.com.
