arXiv subjects

Benedikt Stufler

Publications and source records attributed to Benedikt Stufler.

42 records · Page 3Linked to original sources

arXiv2016

Scaling limits of random outerplanar maps with independent link-weights

The scaling limit of large simple outerplanar maps was established by Caraceni using a bijection due to Bonichon, Gavoille and Hanusse. The present paper introduces a new bijection between outerplanar maps and trees decorated with ordered sequences of edge-rooted dissections of polygons. We apply this decomposition in order to provide a new, short proof of the scaling limit that also applies to the general setting of first-passage percolation. We obtain sharp tail-bounds for the diameter and recover the asymptotic enumeration formula for outerplanar maps. Our methods also enable us treat subclasses such as bipartite outerplanar maps.

math.PR↗

arXiv2016

Unlabelled Gibbs partitions

We study random composite structures considered up to symmetry that are sampled according to weights on the inner and outer structures. This model may be viewed as an unlabelled version of Gibbs partitions and encompasses multisets of weighted combinatorial objects. We describe a general setting characterized by the formation of a giant component. The collection of small fragments is shown toconverge in total variation toward a limit object following a Pólya-Boltzmann distribution.

math.CO↗

arXiv2016

Gibbs partitions: the convergent case

We study Gibbs partitions that typically form a unique giant component. The remainder is shown to converge in total variation toward a Boltzmann-distributed limit structure. We demon- strate how this setting encompasses arbitrary weighted assemblies of tree-like combinatorial structures. As an application, we establish smooth growth along lattices for small block-stable classes of graphs. Random graphs with n vertices from such classes are shown to form a giant connected component. The small fragments may converge toward different Poisson Boltzmann limit graphs, depending along which lattice we let n tend to infinity. Since proper addable minor-closed classes of graphs belong to the more general family of small block-stable classes, this recovers and generalizes results by McDiarmid (2009).

math.CO↗

arXiv2016

Graph limits of random graphs from a subset of connected $k$-trees

For any set $Ω$ of non-negative integers such that $\{0,1\}\subseteq Ω$ and $\{0,1\}\ne Ω$, we consider a random $Ω$-$k$-tree ${\sf G}_{n,k}$ that is uniformly selected from all connected $k$-trees of $(n+k)$ vertices where the number of $(k+1)$-cliques that contain any fixed $k$-clique belongs to $Ω$. We prove that ${\sf G}_{n,k}$, scaled by $(kH_{k}σ_Ω)/(2\sqrt{n})$ where $H_{k}$ is the $k$-th Harmonic number and $σ_Ω>0$, converges to the Continuum Random Tree $\mathcal{T}_{\sf e}$. Furthermore, we prove the local convergence of the rooted random $Ω$-$k$-tree ${\sf G}_{n,k}^{\circ}$ to an infinite but locally finite random $Ω$-$k$-tree ${\sf G}_{\infty,k}$.

math.PR↗

arXiv2015

Scaling limits of random Pólya trees

Pólya trees are rooted trees considered up to symmetry. We establish the convergence of large uniform random Pólya trees with arbitrary degree restrictions to Aldous' Continuum Random Tree with respect to the Gromov-Hausdorff metric. Our proof is short and elementary, and it shows that the global shape of a random Pólya tree is essentially dictated by a large Galton-Watson tree that it contains. We also derive sub-Gaussian tail bounds for both the height and the width, which are optimal up to constant factors in the exponent.

math.PR↗

arXiv2014

Scaling Limits of Random Graphs from Subcritical Classes

We study the uniform random graph $\mathsf{C}_n$ with $n$ vertices drawn from a subcritical class of connected graphs. Our main result is that the rescaled graph $\mathsf{C}_n / \sqrt{n}$ converges to the Brownian Continuum Random Tree $\mathcal{T}_{\mathsf{e}}$ multiplied by a constant scaling factor that depends on the class under consideration. In addition, we provide subgaussian tail bounds for the diameter $\text{D}(\mathsf{C}_n)$ and height $\text{H}(\mathsf{C}_n^\bullet)$ of the rooted random graph $\mathsf{C}_n^\bullet$. We give analytic expressions for the scaling factor of several classes, including for example the prominent class of outerplanar graphs. Our methods also enable us to study first passage percolation on $\mathsf{C}_n$, where we show the convergence to $\mathcal{T}_{\mathsf{e}}$ under an appropriate rescaling.

math.PR↗