The document discusses different tree structure representations for organizing hierarchical data including classical node-link diagrams, nested sets, layered "icicle" diagrams, outlines and tree views, and nested parenthesis. It provides an example data set of names organized in a nested hierarchical structure.

1. Pedro-Celia Lory Ann Rencel Jestin TREE STRUCTURE

2. Pedro-Celia Lory Ann Rencel Jestin CLASSICAL NODE-LINK DIAGRAMS

3. +------------------------------+ ---------- Pedro-Celia - -----+ Lory Ann Rencel Jestin NESTED SETS

4. LAYERED “ICICLE” DIAGRAMS +-----------------+ Pedro-Celia +---------+--------+-------+ Lory Ann Rencel Jestin +---------------------------+

5. OUTLINES AND TREE VIEWS Pedro-Celia Lory Ann Rencel Jestin

6. NESTED PARENTHESIS Lory Ann, Rencel, Jestin, Pedro-Celia