A Graph Decomposition motivated by the Geometry of Randomized Rounding


Abstract in English

We introduce a graph decomposition which exists for all simple, connected graphs $G=(V,E)$. The decomposition $V = A cup B cup C$ is such that each vertex in $A$ has more neighbors in $B$ than in $A$ and vice versa. $C$ is `balanced: each $v in C$ has the same number of neighbours in $A$ and $B$. These decompositions arise naturally from the behavior of an associated dynamical system (`Randomized Rounding) on $(mathbb{S}^1)^{|V|}$. Connections to judicious partitions and the textsc{MaxCut} problem (in particular the Burer-Monteiro-Zhang heuristic) are being discussed.

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