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A realizer, commonly known as Schnyder woods, of a triangulation is a partition of its interior edges into three oriented rooted trees. A flip in a realizer is a local operation that transforms one realizer into another. Two types of flips…

Computational Geometry · Computer Science 2021-06-29 Sujoy Bhore , Prosenjit Bose , Pilar Cano , Jean Cardinal , John Iacono

We discuss an autoencoder model in which the encoding and decoding functions are implemented by decision trees. We use the soft decision tree where internal nodes realize soft multivariate splits given by a gating function and the overall…

Machine Learning · Computer Science 2014-09-29 Ozan İrsoy , Ethem Alpaydın

Phylogenetic networks are leaf-labelled directed acyclic graphs that are used to describe non-treelike evolutionary histories and are thus a generalization of phylogenetic trees. The hybridization number of a phylogenetic network is the sum…

Data Structures and Algorithms · Computer Science 2016-06-01 Leo van Iersel , Steven Kelk , Nela Lekić , Chris Whidden , Norbert Zeh

This paper introduces a method to extract a hierarchical tree representation from 3D unorganized polygonal data. The proposed approach first extracts a graph representation of the surface, which serves as the foundation for structural…

Graphics · Computer Science 2025-10-21 Diogo de Andrade , Nuno Fachada

We show that Delaunay triangulations and compressed quadtrees are equivalent structures. More precisely, we give two algorithms: the first computes a compressed quadtree for a planar point set, given the Delaunay triangulation; the second…

Computational Geometry · Computer Science 2012-08-27 Maarten Löffler , Wolfgang Mulzer

Let $P$ be a set of $n$ points in the plane. A crossing-free structure on $P$ is a plane graph with vertex set $P$. Examples of crossing-free structures include triangulations of $P$, spanning cycles of $P$, also known as polygonalizations…

Computational Geometry · Computer Science 2013-12-18 Victor Alvarez , Karl Bringmann , Radu Curticapean , Saurabh Ray

Reduction trees are a way of encoding a substitution procedure dictated by the relations of an algebra. We use reduction trees in the subdivision algebra to construct canonical triangulations of flow polytopes which are shellable. We…

Combinatorics · Mathematics 2015-02-16 Karola Mészáros

In this paper, we give a constructive proof of the fact that the treewidth of a graph is at most its divisorial gonality. The proof gives a polynomial time algorithm to construct a tree decomposition of width at most $k$, when an effective…

Discrete Mathematics · Computer Science 2020-05-13 Hans L. Bodlaender , Josse van Dobben de Bruyn , Dion Gijswijt , Harry Smit

Floor-planning is a fundamental step in VLSI chip design. Based upon the concept of orderly spanning trees, we present a simple O(n)-time algorithm to construct a floor-plan for any n-node plane triangulation. In comparison with previous…

Data Structures and Algorithms · Computer Science 2007-05-23 Chien-Chih Liao , Hsueh-I Lu , Hsu-Chun Yen

CSG trees are an intuitive, yet powerful technique for the representation of geometry using a combination of Boolean set-operations and geometric primitives. In general, there exists an infinite number of trees all describing the same 3D…

Artificial Intelligence · Computer Science 2020-09-15 Markus Friedrich , Christoph Roch , Sebastian Feld , Carsten Hahn , Pierre-Alain Fayolle

We study inferring a tree-structured representation from a single image for object shading. Prior work typically uses the parametric or measured representation to model shading, which is neither interpretable nor easily editable. We propose…

Computer Vision and Pattern Recognition · Computer Science 2023-09-14 Chen Geng , Hong-Xing Yu , Sharon Zhang , Maneesh Agrawala , Jiajun Wu

This paper introduces Claycode, a novel 2D scannable code designed for extensive stylization and deformation. Unlike traditional matrix-based codes (e.g., QR codes), Claycodes encode their message in a tree structure. During the encoding…

Graphics · Computer Science 2025-05-14 Marco Maida , Alberto Crescini , Marco Perronet , Elena Camuffo

A tree $\sigma$-spanner of a positively real-weighted $n$-vertex and $m$-edge undirected graph $G$ is a spanning tree $T$ of $G$ which approximately preserves (i.e., up to a multiplicative stretch factor $\sigma$) distances in $G$. Tree…

Data Structures and Algorithms · Computer Science 2017-10-05 Davide Bilò , Feliciano Colella , Luciano Gualà , Stefano Leucci , Guido Proietti

In this paper we give a linear time algorithm for computing the number of spanninig trees in double nested graphs.

Combinatorics · Mathematics 2016-05-17 Fernando Tura

We describe a technique to reorganize topologies of Steiner trees by exchanging neighbors of adjacent Steiner points. We explain how to use the systematic way of building trees, and therefore topologies, to find the correct topology after…

Data Structures and Algorithms · Computer Science 2018-03-13 Aymeric Grodet , Takuya Tsuchiya

In this paper, we give polynomial-time algorithms that can take a graph G with a given combinatorial embedding on an orientable surface S of genus g and produce a planar drawing of G in R^2, with a bounding face defined by a polygonal…

Computational Geometry · Computer Science 2009-08-13 Christian A. Duncan , Michael T. Goodrich , Stephen G. Kobourov

Let $G$ be a 3-connected planar graph. Define the co-tree of a spanning tree $T$ of $G$ as the graph induced by the dual edges of $E(G)-E(T)$. The well-known cut-cycle duality implies that the co-tree is itself a tree. Let a $k$-tree be a…

Discrete Mathematics · Computer Science 2024-06-05 Christian Ortlieb , Jens M. Schmidt

Treewidth is a well-known graph invariant with multiple interesting applications in combinatorics. On the practical side, many NP-complete problems are polynomial-time (sometimes even linear-time) solvable on graphs of bounded treewidth. On…

Category Theory · Mathematics 2021-05-13 Zoltan A. Kocsis , Benjamin Merlin Bumpus

Representations of planar triangulations as contact graphs of a set of internally disjoint homothetic triangles or of a set of internally disjoint homothetic squares have received quite some attention in recent years. In this paper we…

Computational Geometry · Computer Science 2020-04-14 Stefan Felsner , Hendrik Schrezenmaier , Raphael Steiner

Tree-width and path-width are widely successful concepts. Many NP-hard problems have efficient solutions when restricted to graphs of bounded tree-width. Many efficient algorithms are based on a tree decomposition. Sometimes the more…

Data Structures and Algorithms · Computer Science 2016-06-22 Martin Fürer