diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 68da8e7..e0c425b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,7 +8,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.21.x, 1.22.x, 1.23.x]
+        go-version: [1.23.x, 1.24.x, 1.25.x]
         platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
     steps:
diff --git a/segment.go b/segment.go
index 122a28d..4e2dbad 100644
--- a/segment.go
+++ b/segment.go
@@ -243,3 +243,24 @@ type Synonym interface {
 
 	Size() int
 }
+
+// NestedSegment is an optional interface that a Segment may implement
+// to provide access to nested document relationships within that segment.
+type NestedSegment interface {
+	Segment
+	// Ancestors returns a slice of ancestor IDs for the given document ID.
+	// If the document has no ancestors or if the segment does not support nested documents,
+	// a slice containing only the document ID itself is returned.
+	Ancestors(docID uint64, prealloc []index.AncestorID) []index.AncestorID
+
+	// CountRoot returns the number of root documents in the segment, excluding any documents
+	// that are marked as deleted in the provided bitmap. If the segment does not support nested
+	// documents, it returns the total document count minus the count of deleted documents.
+	// A root document is defined as a document that is not a child of any other document.
+	CountRoot(deleted *roaring.Bitmap) uint64
+
+	// AddNestedDocuments updates the provided bitmap to include all nested documents
+	// associated with documents marked as deleted in the bitmap. This ensures that when
+	// a parent document is deleted, all its nested child documents are also considered deleted.
+	AddNestedDocuments(deleted *roaring.Bitmap) *roaring.Bitmap
+}