| n < # wlar, n < # apebs ⊦ v ∈ vols ∧ m < # vols[v] ∧ vols[v][m] = ⌜n1⌝ ∧ n ≠ n0 ∧ n1 ≠ n0 ∧ apebs[n].vidhdr.valid? ∧ apebs[n].vidhdr.vol = v ∧ apebs[n].vidhdr.leb = m ∧ wlar[n].status ≠ used ∧ valid-ebatbl(apebs, wlar, vols, n0) → valid-ebatbl(apebs, wlar[n, wl-entry(m0, used)][n1, wl-entry(m1, erasing)], vols[v, vols[v][m, ⌜n⌝ ]], n0) |