Weighted Laplacian Spread Conjecture

Let GG be a weighted graph on nn vertices in which every edge weight lies in [0,1][0,1], and let GcG^c be its weighted complement, obtained by replacing each edge weight wijw_{ij} by 1wij1-w_{ij}. The algebraic connectivity of a weighted graph is denoted by λ2\lambda_2.

Weighted Laplacian Spread Conjecture. One has

λ2(G)+λ2(Gc)1.\lambda_2(G)+\lambda_2(G^c)\geq 1.

This is the natural extension of the symmetric formulation of the Laplacian Spread Conjecture from simple graphs to weighted graphs; the paper reports supporting investigations but no resolution.

Sources & referencesView supporting material

Primary source

Wayne Barrett, Emily Evans, H. Tracy Hall and Mark Kempton, “New conjectures on algebraic connectivity and the Laplacian spread of graphs”, arXiv:2201.04225 (2022).

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