MS&E 319: Approximation Algorithms


Administrative Information

-          Instructor: Amin Saberi (Office Hours: by appointment)

-          Lectures:  Monday – Wednesday 2:15 pm– 3:30 pm at 540-103

-          Course assistant: Vahideh Manshadi (Office hours: Wednesday 12:30 pm – 2 pm at Huang Engineering, Room 16)

Text book: Some of the lectures and exercises are taken from:

-          Approximation Algorithms, by Vijay V. Vazirani, Springer-Verlag, Berlin, 2001.

-          The Design of Approximation Algorithms, David P. Williamson and David B. Shmoys, Cambridge University Press, New York, NY, USA, 2011.

 

Description: This course is on special topics in approximation algorithms with an emphasis on network optimization. The length and selection of topics will depend on the interest and enthusiasm of the students and the instructor. We will consider that a feature.


Topics:

Lecture 1 & 2 : Primal-dual framework, Set cover (primal-dual and dual fitting algorithms), Facility location (primal-dual and dual fitting, factor revealing linear programs), Steiner Forest

References:  

-          Chapters 12, 13, 15, and 24 of Vazirani’s book

-          K. Jain, M. Mahdian, E. Markakis , A. Saberi, and V. Vazirani, A Greedy Facility Location Algorithm Analyzed using Dual-Fitting with Factor-revealing LP, Journal of the ACM, 2003.

-          M.X. Goemans and D.P. Williamson, A General Approximation Technique for Constrained Forest Problems, SIAM Journal on Computing, 1995. 

Lecture 3 (taught by Luca Trevisan): Approximating sparsest cut spectrally, Cheeger's inequality

References:  Luca's lecture notes


Lecture 4 & 5: An O(log n) approximation algorithm for sparsest cut, Relation to multicommodity flow LP and metric embedding, Frechet embeddings and embedding metrics into l1 metrics, Applications to minimum cut linear arrangement and balanced cut

References:

-          Chapter 21 of Vazirani’s book

-          P. Indyk and J. Matousek, Low-Distortion Embeddings of Finite Metric Spaces, in Handbook of Discrete and Computational Geometry, 2004.

     Lecture 6: Probabilistic approximation of metrics by tree metrics

    References:

-          J. Fakcharoenphol, S. Rao and K. Talwar, A Tight Bound on Approximating Arbitrary Metrics by Tree Metrics, STOC, 2003. 

-          Chapter 8 of Williamson-Shmoys’s book

    Lecture 7&8: Applications of tree metrics: bandwidth minimization (linear arrangement), oblivious routing, and minimum bisection problem

    References:

-          Chapter 8.7 of Williamson-Shmoys’s book

-          Chapter 15.2 and 15.3 of Williamson-Shmoys’s book

-          H. Räcke, Optimal Hierarchical Decompositions for Congestion Minimization in Networks, STOC, 2008.

 

    Lecture 9: Semi-definite Programing, max-cut, and quadratic programing

    References:

-          Chapter 26 Vazirani’s book

-          M.X. Goemans and D.P. Williamson, Improved Approximation Algorithms for Maximum Cut and Satisfiability Problems Using Semidefinite Programming, Journal

of the ACM, 1995.

-        Chapter 6.3 of Williamson-Shmoys’s book

-        Y. Nesterov, Semidefinite relaxation and nonconvex quadratic optimization, Optimization Methods and Software, 1998.

 

Lecture 10: An O(\sqrt{log(n)}) approximation algorithm for the sparsest cut problem

References:

-        S. Arora, S. Rao, and U. Vazirani, Expander Flows, Geometric Embeddings and Graph Partitioning, STOC, 2004

-      Chapter 15.4 of Williamson-Shmoys’s book

-      S. Arora, J. R. Lee, and A. Naor , Euclidean distortion and the Sparsest Cut, Journal of the American Mathematical Society 21, 2008. 

-      S. Arora, J. R. Lee, and A. Naor,  Frechet embeddings of negative type metrics, Discrete and Computational Geometry 38, 2007. 

 

Lecture 11: Asymmetric Traveling Salesman Problem (ATSP), thin trees, and Goodyn’s conjecture

References:

-      M. Held and R. Karp. The traveling salesman problem and minimum spanning trees. Operations Research,1970.

-      A. Asadpour, M. Goemans, A. Madry, S. Oveis Gharan, A. Saberi, An O(log n/log log n)-Approximation Algorithm for the Asymmetric Traveling Salesman Problem, SODA 2010. 

-      L. A. Goddyn. Some open problems i like. Available at: http://people.math.sfu.ca/~goddyn/Problems/problems.html 

 

Lecture 12 & 13: Sampling thin trees using maximum entropy sampling

References:

-        A. Asadpour, M. Goemans, A. Madry, S. Oveis Gharan, A. Saberi, An O(log n/log log n)-Approximation Algorithm for the Asymmetric Traveling Salesman Problem, SODA 2010. 

 

Lecture 14: (taught by Jon Vondrak) Dependent randomized rounding

References:

-        C. Chekuri, J. Vondrak, R. Zenklusen, Dependent randomized rounding via exchange properties of combinatorial structures, FOCS 2010

 

Lecture 15 & 16: Traveling Salesman Problem (TSP)

References:

-        S. Oveis Gharan, A. Saberi, M. Singh, A Randomized Rounding Approach to the Traveling Salesman Problem.

-        A. A. Benczur, Cut structures and randomized algorithms in edge-connectivity problems, PhD thesis, 1997.

-        T. Fleiner and A. Frank. A quick proof for the cactus representation of mincuts, 2009.

 

   Homeworks:

1.    HW#1 Due date: May/05/11