| ∀ vols0, v. # vols0 < # vols → true → (v ∈ to-vtbl(vols0) ↔ v ∈ vols0) ⊦ v ∈ to-vtbl(vols) ↔ v ∈ vols, vols = ∅ |
⊦ vols = vols0 ↔ (∀ v. (v ∈ vols ↔ v ∈ vols0) ∧ vols[v] = vols0[v])
∀ vols0, v. # vols0 < # vols → true → (v ∈ to-vtbl(vols0) ↔ v ∈ vols0) ⊦ v ∈ to-vtbl(vols) ↔ v ∈ vols, ∀ v. (v ∈ vols ↔ v ∈ ∅) ∧ vols[v] = (∅)[v]
Used terms: ∅, vols