4. Provable algorithms at the KS threshold
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Analyze BP
Problem 4.1.
[Elchanan Mossel] For the symmetric 2-groups SBM, show that BP (with random initialization) achieves $\varepsilon$ correlation with the truth, above the KS bound. -
BP with good initialization
Problem 4.2.
[Lenka Zdeborová] Run BP with a ‘good’ initialization (e.g. using a spectral method based on the non-backtracking walk matrix). Show that it achieves the optimal overlap with the truth. -
Analyze Gibbs sampling
Problem 4.3.
[Lenka Zdeborová] For the symmetric 2-groups SBM, show that Gibbs sampling achieves $\varepsilon$ correlation with the truth, above the KS bound.
Cite this as: AimPL: Connecting communities via the block model, available at http://aimpl.org/blockmodel.