The Lovász Theta Function for Random Regular Graphs and Community Detection in the Hard Regime
| Autor: | Cristopher Moore, Robert Kleinberg, Jess Banks |
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| Rok vydání: | 2019 |
| Předmět: |
Random graph
000 Computer science knowledge general works General Computer Science Degree (graph theory) General Mathematics Theta function Function (mathematics) Computer Science::Computational Complexity Mathematical proof Upper and lower bounds Combinatorics Computer Science Graph coloring Mathematics |
| Zdroj: | SIAM Journal on Computing. 48:1098-1119 |
| ISSN: | 1095-7111 0097-5397 |
| DOI: | 10.1137/18m1180396 |
| Popis: | We derive upper and lower bounds on the degree d for which the Lovasz theta function, or equivalently sum-of-squares proofs with degree two, can refute the existence of a k-coloring in random regular graphs G(n,d). We show that this type of refutation fails well above the k-colorability transition, and in particular everywhere below the Kesten-Stigum threshold. This is consistent with the conjecture that refuting k-colorability, or distinguishing G(n,d) from the planted coloring model, is hard in this region. Our results also apply to the disassortative case of the stochastic block model, adding evidence to the conjecture that there is a regime where community detection is computationally hard even though it is information-theoretically possible. Using orthogonal polynomials, we also provide explicit upper bounds on the theta function for regular graphs of a given girth, which may be of independent interest. |
| Databáze: | OpenAIRE |
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