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Edit distances between merge trees of scalar fields have many applications in scientific visualization, such as ensemble analysis, feature tracking or symmetry detection. In this paper, we propose branch mappings, a novel approach to the…

Computational Geometry · Computer Science 2022-08-12 Florian Wetzels , Heike Leitte , Christoph Garth

We compute the compactly supported Euler characteristic of the space of degree $d$ irreducible polynomials in $n$ variables with real coefficients and show that the values are given by the digits in the so-called balanced binary expansion…

Algebraic Topology · Mathematics 2020-11-12 Trevor Hyde

Deciding whether a collection of unrooted trees is compatible is a fundamental problem in phylogenetics. Two different graph-theoretic characterizations of tree compatibility have recently been proposed. In one of these, tree compatibility…

Discrete Mathematics · Computer Science 2012-10-16 Sudheer Vakati , David Fernández-Baca

We prove that if a graph has a tree-decomposition of width at most w, then it has a tree-decomposition of width at most w with certain desirable properties. We will use this result in a subsequent paper to show that every 2-connected graph…

Combinatorics · Mathematics 2018-04-17 Thanh N. Dang , Robin Thomas

A polar hypersurface P of a complex analytic hypersurface germ, f=0, can be investigated by analyzing the invariance of certain Newton polyhedra associated to the image of P, with respect to suitable coordinates, by certain morphisms…

Algebraic Geometry · Mathematics 2007-05-23 Pedro Daniel Gonzalez Perez , Evelia Garcia Barroso

It remains unknown if every prismatoid has a nonoverlapping edge-unfolding, a special case of the long-unsolved "D\"urer's problem." Recently nested prismatoids have been settled [Rad24] by mixing (in some sense) the two natural unfoldings,…

Computational Geometry · Computer Science 2026-03-25 Joseph O'Rourke

In the study of the constant in Ahlfors' second fundamental theorem involving a set E_{q} of q points, branch values of covering surfaces outside E_{q} bring a lot of troubles. To avoid this situation, for a given surface S, it is useful to…

Complex Variables · Mathematics 2018-10-17 Zonghan Sun , Guangyuan Zhang

We present three new inequalities tying the signature, the simplicial volume and the Euler characteristic of surface bundles over surfaces. Two of them are true for any surface bundle, while the third holds on a specific family of surface…

Geometric Topology · Mathematics 2020-12-03 Michelle Bucher , Caterina Campagnolo

Several min-max relations in graph theory can be expressed in the framework of the Erd\H{o}s-P\'osa property. Typically, this property reveals a connection between packing and covering problems on graphs. We describe some recent techniques…

Discrete Mathematics · Computer Science 2016-12-14 Jean-Florent Raymond , Dimitrios M. Thilikos

A branched covering map of surfaces induces a map in the opposite direction between their arc complexes. We represent a branched covering map combinatorially using what we call a lifting picture, and use this representation to computably…

Combinatorics · Mathematics 2020-09-15 Cyrus Peterpaul

We study regular coverings of graphs and manifolds with a focus on properties of the heat equation. In particular, we look at stochastic incompleteness, the Feller property and uniform transience; and investigate the connection between the…

Functional Analysis · Mathematics 2018-02-21 Bobo Hua , Florentin Münch , Radosław K. Wojciechowski

In this paper, two open conjectures are disproved. One conjecture regards independent coverings of sparse partite graphs, whereas the other conjecture regards orthogonal colourings of tree graphs. A relation between independent coverings…

Combinatorics · Mathematics 2022-01-11 Kyle MacKeigan

It is a classical result that an unrooted tree $T$ having positive real-valued edge lengths and no vertices of degree two can be reconstructed from the induced distance between each pair of leaves. Moreover, if each non-leaf vertex of $T$…

Combinatorics · Mathematics 2017-07-26 Stefan Gruenewald , Katharina T. Huber , Vincent Moulton , Mike Steel

The $c$-packedness property, proposed in 2010, is a geometric property that captures the spatial distribution of a set of edges. Despite the recent interest in $c$-packedness, its utility has so far been limited to Fr\'echet distance…

Computational Geometry · Computer Science 2025-05-13 Lindsey Deryckere , Joachim Gudmundsson , André van Renssen , Yuan Sha , Sampson Wong

A canonical branched covering over each sufficiently good simplicial complex is constructed. Its structure depends on the combinatorial type of the complex. In this way, each closed orientable 3-manifold arises as a branched covering over…

Geometric Topology · Mathematics 2007-05-23 Ivan Izmestiev , Michael Joswig

We prove that Stein surfaces with boundary coincide up to orientation preserving diffeomorphisms with simple branched coverings of $\B^4$ whose branch set is a positive braided surface. As a consequence, we have that a smooth oriented…

Geometric Topology · Mathematics 2009-10-31 Andrea Loi , Riccardo Piergallini

Braided embeddings are embeddings to a product disc bundle so the projection to the first factor is a branched cover. In this paper, we study which branched covers lift to braided embeddings, which is a generalization of the Borsuk-Ulam…

Geometric Topology · Mathematics 2021-04-09 Sudipta Kolay

We study the use of the Euler characteristic for multiparameter topological data analysis. Euler characteristic is a classical, well-understood topological invariant that has appeared in numerous applications, including in the context of…

Algebraic Topology · Mathematics 2021-02-17 Gabriele Beltramo , Rayna Andreeva , Ylenia Giarratano , Miguel O. Bernabeu , Rik Sarkar , Primoz Skraba

The initial value problem is well-defined on a class of spacetimes broader than the globally hyperbolic geometries for which existence and uniqueness theorems are traditionally proved. Simple examples are the time-nonorientable spacetimes…

General Relativity and Quantum Cosmology · Physics 2007-05-23 John L. Friedman

This paper describes connected components of the strata of holomorphic abelian differentials on marked Riemann surfaces with prescribed degrees of zeros. Unlike the case for unmarked Riemann surfaces, we find there can be many connected…

Geometric Topology · Mathematics 2019-06-10 Aaron Calderon