Proof step 3 from proof prefix-subseteq-dom-nodes-rev (previous step)
⊦ st0 ⊑ st
↔ dom st0 ⊆ dom st
∧ (∀ n.
n ∈ st0 ∧ n ∈ st
→ st0[n].list ⊑ st[n].list ∧ st0[n].ladrlist ⊑ st[n].ladrlist ∧ # st0[n].list = # st0[n].ladrlist
∧ # st[n].list = # st[n].ladrlist)