Imports
import CLRSLean.FourthEdition.Chapter_18.Section_18_1_B_Tree_Model import CLRSLean.FourthEdition.Chapter_18.Section_18_1_B_Tree_Model.Search import CLRSLean.FourthEdition.Chapter_18.Section_18_1_B_Tree_Model.HeightBound import CLRSLean.FourthEdition.Chapter_18.Section_18_1_B_Tree_Model.RunningTime import CLRSLean.FourthEdition.Chapter_18.Section_18_2_B_Tree_Insertion import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Invariant import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Rotation import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Repair import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Preservation import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Reassembly import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.MergeReassembly import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.RotationBounds import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.RotationReassembly import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.ComposedPreservation import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.KeyMultiset import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.ExactReassembly import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Exact import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Subset import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.SameDepthHeight import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Sorted import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.ChildBounded import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.Occupancy import CLRSLean.FourthEdition.Chapter_18.Section_18_3_B_Tree_Deletion.WellFormed

Chapter 18 — B-Trees

This is the canonical CLRS fourth-edition chapter guide during the migration period.

Current source

Sections 18.1--18.3 are native fourth-edition sections (definition of B-trees, basic operations on B-trees, and deleting a key from a B-tree), imported directly from Section 18.1, Section 18.2, and Section 18.3. Section 18.1 includes the nested search, height-bound, and running-time developments; section 18.3 includes the nested deletion-invariant and reassembly developments. Declarations retain the CLRS.Chapter18 namespace during the compatibility period; the third-edition-numbered imports CLRSLean.Chapter_18 and CLRSLean.Chapter_18.Section_18_* forward to these sources.

Coverage boundary

The existing B-tree search insertion deletion and invariant developments are reused.

See docs/clrs-fourth-edition-map.csv for the section-level mapping and docs/migrations/clrs4.md for compatibility and deprecation policy.