4.1. Finding Root and Leaf Nodes4.2. Finding Subtrees4.3. Finding Levels and Paths in a Tree4.4. Functions in the Nested Sets Model4.5. Deleting Nodes and Subtrees4.6. Closing Gaps in the Tree4.7. Summary Functions on Trees4.8. Inserting and Updating Trees4.9. Converting Nested Sets Model to Adjacency List Model4.10. Converting Adjacency List Model to Nested Sets Model4.11. Separation of Edges and Nodes4.12. Comparing Nodes and Structure4.13. Nested Sets Code in Other Languages