theorem
Hex.GraphIso.Nauty.Sparse.Target.score_perm
{n first : Nat}
(G : SparseGraph n)
(lab out ptn : Array Nat)
(level : Nat)
(s t : Scratch)
(hp : lab.toList.Perm (List.range n))
(hq : out.toList.Perm (List.range n))
(hs : ptn.size = n)
(hend : ptn[n - 1]! ≤ level)
(hi : Index.Valid n lab ptn level s.cellstart s.cellend)
(hj : Index.Valid n out ptn level t.cellstart t.cellend)
(heq : Equitable (Graph.context G) level lab ptn)
(hperm : cellsPerm ptn level lab out)
(hf : first ∈ nontrivial (cells ptn level n))
:
score (Graph.ofGraph G) lab s (nontrivial (cells ptn level n)) first = score (Graph.ofGraph G) out t (nontrivial (cells ptn level n)) first
In an equitable partition the partial-join score is unchanged by reordering vertices inside cells, even when the representative changes.