MAP Estimation, Message Passing, and Perfect Graphs
Tony Jebara
Abstract:
Efficiently finding the maximum a posteriori (MAP) configuration of a graphical model is an important problem which is often implemented using message passing algorithms. The optimality of such algorithms is only well established for singlyconnected graphs and other limited settings. This article extends the set of graphs where MAP estimation is in P and where message passing recovers the exact solution to socalled perfect graphs. This result leverages recent progress in defining perfect graphs (the strong perfect graph theorem), linear programming relaxations of MAP estimation and recent convergent message passing schemes. The article converts graphical models into nand Markov random fields which are straightforward to relax into linear programs. Therein, integrality can be established in general by testing for graph perfection. This perfection test is performed efficiently using a polynomial time algorithm. Alternatively, known decomposition tools from perfect graph theory may be used to prove perfection for certain families of graphs. Thus, a general graph framework is provided for determining when MAP estimation in any graphical model is in P, has an integral linear programming relaxation and is exactly recoverable by message passing.
Keywords: null
Pages: 258267
PS Link:
PDF Link: /papers/09/p258jebara.pdf
BibTex:
@INPROCEEDINGS{Jebara09,
AUTHOR = "Tony Jebara
",
TITLE = "MAP Estimation, Message Passing, and Perfect Graphs",
BOOKTITLE = "Proceedings of the TwentyFifth Conference Annual Conference on Uncertainty in Artificial Intelligence (UAI09)",
PUBLISHER = "AUAI Press",
ADDRESS = "Corvallis, Oregon",
YEAR = "2009",
PAGES = "258267"
}

