| ⊦ r ∈ zh ∧ zh[r] = mkznode(rp0, zbrar, boolvar, false, height0) ∧ ((btree(rp, r, adr, height, false, ri, iast, as, alladrs, nstat) * P))(zh) → ((btree(rp, r, adr, height, true, ri, iast, as -- adr, alladrs, nstat) * P))(zh[r, mkznode(rp0, zbrar, boolvar, true, height0)]) |