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June 2015 Random lattice triangulations: Structure and algorithms
Pietro Caputo, Fabio Martinelli, Alistair Sinclair, Alexandre Stauffer
Ann. Appl. Probab. 25(3): 1650-1685 (June 2015). DOI: 10.1214/14-AAP1033


The paper concerns lattice triangulations, that is, triangulations of the integer points in a polygon in $\mathbb{R}^{2}$ whose vertices are also integer points. Lattice triangulations have been studied extensively both as geometric objects in their own right and by virtue of applications in algebraic geometry. Our focus is on random triangulations in which a triangulation $\sigma$ has weight $\lambda^{|\sigma|}$, where $\lambda$ is a positive real parameter, and $|\sigma|$ is the total length of the edges in $\sigma$. Empirically, this model exhibits a “phase transition” at $\lambda=1$ (corresponding to the uniform distribution): for $\lambda<1$ distant edges behave essentially independently, while for $\lambda>1$ very large regions of aligned edges appear. We substantiate this picture as follows. For $\lambda<1$ sufficiently small, we show that correlations between edges decay exponentially with distance (suitably defined), and also that the Glauber dynamics (a local Markov chain based on flipping edges) is rapidly mixing (in time polynomial in the number of edges in the triangulation). This dynamics has been proposed by several authors as an algorithm for generating random triangulations. By contrast, for $\lambda>1$ we show that the mixing time is exponential. These are apparently the first rigorous quantitative results on the structure and dynamics of random lattice triangulations.


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Pietro Caputo. Fabio Martinelli. Alistair Sinclair. Alexandre Stauffer. "Random lattice triangulations: Structure and algorithms." Ann. Appl. Probab. 25 (3) 1650 - 1685, June 2015.


Published: June 2015
First available in Project Euclid: 23 March 2015

zbMATH: 1293.52011
MathSciNet: MR3325284
Digital Object Identifier: 10.1214/14-AAP1033

Primary: 60K35
Secondary: 05C81, 68W20

Rights: Copyright © 2015 Institute of Mathematical Statistics


Vol.25 • No. 3 • June 2015
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