| n < nused, nused ≤ BRANCH_SIZE, # zbrar0 = # zbrar1, # zbrar0 = BRANCH_SIZE ⊦ iast0 ⊆ iast1 ∧ unmodified(adr, mkznode(rp0, zbrar0, bv, false, nused), iast0) ∧ unmodified(adr, mkznode(rp1, zbrar1, bv, false, nused), iast1) → (zbrar1[n].key = zbrar0[n].key ↔ true) |