theorem
Hex.GraphIso.Nauty.Sparse.Max.SweepInput.reference_filters
{n k : Nat}
{G : Sparse.Colored n k}
{tcLevel fuel boundary tv tv1 : Nat}
{l : Loop n}
{bs fs : List Nat}
{cell : VSet n}
{st out : State n}
{parents : Parents n}
{targets : List Nat}
{key : Key n}
{short : Bool}
(h : SweepInput G tcLevel l bs fs (some tv) cell st parents)
:
have c := Loop.cell G.graph tcLevel l;
have R := State.refined (Graph.ofGraph G.graph) l.node.level l.node.numcells l.node.entry;
have left := Generic.Policy.leaveChild tv out;
have small := if short = true then Generic.Policy.shortprune cell left else cell;
have filtered := if (!l.first && tv == tv1) = true then Generic.Policy.longprune small left else small;
Generic.node false (Graph.ofGraph G.graph) (n + 2) tcLevel fuel (l.node.level + 1) (c.numcells + 1)
(Generic.Policy.child l.first l.node.level c.tc tv st) = (Generic.Exit.unwind l.node.level short, out) →
Generation.PathCover G.graph tcLevel boundary l.node.level R c.tc c.len targets key cell (some tv) →
Generation.PathCover G.graph tcLevel boundary l.node.level R c.tc c.len targets key filtered (some tv)
Both filters after an actual off-path child preserve the richer reference ledger. The complete native child call supplies receiver pair validity; the recovered partition transports it to the frozen target.