5 Sets with unverified elements
Elements are verified values or marks; the equality atom yields \(Z\) whenever a mark is involved — even a mark with itself.
\(\mathrm{mem}(z, S)=F\) for every mark \(z\) and every list \(S\): membership is an existential fold with strict witnesses.
A marked set is not provably a subset of itself; reflexivity of set equality fails — inherited from the tables, not postulated.