Proof step 5 from proof lf-mapped-info (previous step)
⊦ valid-ebatbl(apebs, wlar, vols, n0)
↔ (∀ v, m, n.
vols[v][m] = ⌜n⌝ ∧ v ∈ vols ∧ m < # vols[v]
↔ wlar[n].status = used ∧ n < # apebs ∧ n < # wlar ∧ apebs[n].vidhdr.valid? ∧ apebs[n].vidhdr.vol = v ∧ apebs[n].vidhdr.leb = m
∧ n ≠ n0)