CS6130 Advanced Graph Algorithms

Date Topic Reference
Aug 1 Introduction + Administrative announcements None
Aug 2 Network Flows and Cuts CLRS Section 26.1
Aug 6 Image Segmentation: An application Kleinberg and Tardos Section 7.10
Aug 7 Review of Ford Fulkerson Method CLRS Section 26.1, 26.2
Aug 8 Proof of Max-Flow Min-cut theorem and Push Relabel Algorithm CLRS Section 26.2, 26.4
Aug 9 Push Relabel Algorithm (invariants) CLRS Section 26.4
Aug 13 Push Relabel Algorithm (analysis) Roughgarden's notes on Push-Relabel
Aug 14 Bipartite Matchings and Flows (reduction) CLRS Section 26.3
Aug 20 Proof of Halls Theorem via max-flow min-cut theorem Kleinberg and Tardos Section 7.3
Aug 21 Dulmage Mendelsohn Decomposition Notes (Proof in class was via network flows)
Aug 22 Hopcroft Karp Algorithm Graph Theory book by DB West.
Aug 23 Hopcroft Karp Algorithm (continued) Notes by Sameer Khuller
Aug 27 Matchings without short augmenting paths.
Non-bipartite matchings Tutte Berge formula.
Aug 28 Why does layered network not work for non-bipartite graphs?
Need to define blossoms. Defintion of a blossom and examples.
Aug 29 Correctness of blossom shrinking.
Aug 30 Quiz 1
Sept 3 Discussion of Quiz 1 answers and grading policy.
Sept 4 An implementation of Edmonds algorithm using union-find.
See Notes by Uri Zwick
Sept 5-6 Gallai Edmonds Decomposition Theorem.
Notes coming up!!
Sept 9 A Detour: TSP, inapproximability, Metric TSP, 2-approx and 3/2-approx. algo.
See Roughgarden's Notes on TSP (Section 1 and Section 2)
Sept 12 Introduction to LPs, Example, Duality.
Class Notes by TA. For additional reading, see Chapter 7 of DPV book on Algorithms.
Sept 13 Forumulating LP for matching, vertex cover.
Class Notes by TA.
Sept 17 Maximum Weight Perfect Matching.
Class Notes by TA.
Sept 18 Primal-Dual Algorithm for Weighted Bipartite Matching.
Class Notes by TA.
Sept 19 Primal Dual Algorithm for Shortest Path.
Class Notes by TA.
Sept 20 Primal Dual Algorithm for Shortest Path (continued).
Approximation Algorithms by Shmoys and Williamsons (Section 7.3)
Sept 24 Weighted Vertex Cover.
Class Notes by TA.
Sept 24 Weighted Vertex Cover.
Class Notes by TA.
Sept 25 Complementary Slackness (derivation) and a general scheme for approximation algorithms.
Class Notes by TA.
Sept 26 Steiner Tree Problem and a simple 2-approximation.
Class Notes by TA.
Sept 26 Generalized Steiner Tree Problem.
Shmoys and Williamsons. Section 7.4
Sept 27 Generalized Steiner Tree Problem (continued).
Shmoys and Williamsons. Section 7.4
Oct 3 LP for Max-flow and its Dual. Interpretation of Dual.
Class Notes by TA.
Oct 4 Min-Cost Max Flow. Relation with other problems. Successive Shortest path algo.
Class Notes by TA.
Oct 9 Min-Cost Max Flow. Primal Dual and Complementary Slackness conditions.
Class Notes by TA.
Oct 10 Min-Cost Max Flow continued.
Class Notes by TA.
Oct 11 Min-Cost Max Flow continued.
Class Notes by TA.
Oct 15 Class cancelled (Prof. Karp's visit)
Oct 16 Introduction to stable matchings. Notes emailed to class.
Oct 17 Properties of the stable matching. Class Notes by TA.
Oct 17 Variants of the stable matching problem. Class Notes by TA.
Oct 22 Student Presentation (Flow algorithms for planar graphs)
Oct 23 Maximum cardinality weakly stable matchings
Kiraly's paper (2/3 approx. for ties on one side)
Oct 24 Maximum cardinality popular matchings
Kavitha's paper.
Oct 25 Maximum cardinality popular matchings continued
Kavitha's paper.
Oct 29 Student Presentation (Flow Games)
Oct 30 An application of stable matching: Dinitz Problem. Chapter 33, Proofs from the book.
Oct 31 An application of stable matching: Dinitz Problem -- continued. Chapter 33, Proofs from the book.
Nov 1 List coloring of Planar Graphs. Chapter 34, Proofs from the book.
Nov 5--6 Edge Coloring and a additive one approximation algorithm. Chapter 7, DB West, Introduction to Graph Theory.