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We prove a generalization of the Shapiro-Shapiro conjecture on Wronskians of polynomials, allowing the Wronskian to have complex conjugate roots. We decompose the real Schubert cell according to the number of real roots of the Wronski map,…

Algebraic Geometry · Mathematics 2021-07-12 Jake Levinson , Kevin Purbhoo

We construct a large family of normal $\kappa$-complete $\mathbb{R}_\kappa$-embeddable non-special $\kappa^+$-Aronszajn trees which have no club isomorphic subtrees using an instance of the proxy principle of Brodsky-Rinot.

Logic · Mathematics 2022-11-29 John Krueger

Tree containment problem is a fundamental problem in phylogenetic study, as it is used to verify a network model. It asks whether a given network contain a subtree that resembles a binary tree. The problem is NP-complete in general, even in…

Populations and Evolution · Quantitative Biology 2017-02-15 Andreas Gunawan

We consider an infinite sequence of rooted trees naturally emerging in a number-theoretical context. We advance some ideas on its structure by discussing some elementary properties. Some of those properties are shown to be related to…

Number Theory · Mathematics 2023-01-10 Roberto Conti , Pierluigi Contucci

General results on multiplicative lattices found recently by Facchini, Finocchiaro and Janelidze have been studied in the particular case of groups by Facchini, de Giovanni and Trombetti. In this paper we prove that these results hold not…

Group Theory · Mathematics 2022-04-26 Alberto Facchini

It has recently been shown that the NP-hard problem of calculating the minimum number of hybridization events that is needed to explain a set of rooted binary phylogenetic trees by means of a hybridization network is fixed-parameter…

Populations and Evolution · Quantitative Biology 2012-03-20 Leo van Iersel , Simone Linz

We study the relationship between Iitaka fibrations and the conjecture on the existence of complements, assuming the good minimal model conjecture. In one direction, we show that the conjecture on the existence of complements implies the…

Algebraic Geometry · Mathematics 2023-01-13 Guodu Chen , Jingjun Han , Jihao Liu

We present a new definition of non-ambiguous trees (NATs) as labelled binary trees. We thus get a differential equation whose solution can be described combinatorially. This yields a new formula for the number of NATs. We also obtain…

Discrete Mathematics · Computer Science 2021-03-26 Bérénice Delcroix-Oger , Florent Hivert , Patxi Laborde-Zubieta , Jean-Christophe Aval , Adrien Boussicault

Plural (or multiple-conclusion) cuts are inferences made by applying a structural rule introduced by Gentzen for his sequent formulation of classical logic. As singular (single-conclusion) cuts yield trees, which underlie ordinary natural…

Logic · Mathematics 2013-02-15 K. Dosen , Z. Petric

Background: One-dimensional protein structures such as secondary structures or contact numbers are useful for three-dimensional structure prediction and helpful for intuitive understanding of the sequence-structure relationship. Accurate…

Biomolecules · Quantitative Biology 2007-07-09 Akira R. Kinjo , Ken Nishikawa

We introduce in this section an Algebraic and Combinatorial approach to the theory of Numbers. The approach rests on the observation that numbers can be identified with familiar combinatorial objects namely rooted trees, which we shall here…

Number Theory · Mathematics 2011-01-18 Edinah K. Gnang

This paper finally fully elaborates the tree pulldown method used by one of us (Harrington) to settle McLaughlin's conjecture. This method enables the construction of a computable tree $T_0$ whose paths are incomparable over $0^{(\alpha)}$…

Logic · Mathematics 2025-04-22 Leo A. Harrington , Peter M. Gerdes

In analogy to other concepts of a similar nature, we define the inducibility of a rooted binary tree. Given a fixed rooted binary tree $B$ with $k$ leaves, we let $\gamma(B,T)$ be the proportion of all subsets of $k$ leaves in $T$ that…

Combinatorics · Mathematics 2016-01-27 Éva Czabarka , László A. Székely , Stephan Wagner

We calculate the spectrum of torsional vibrations of a double-stranded structure that models the double helix of the DNA. We come to the conclusion that within the framework of the model elementary excitations may display an asymmetry as…

Soft Condensed Matter · Physics 2007-05-23 V. L. Golo , E. I. Kats , Yu. M. Yevdokimov

The secondary structure of ribonucleic acid (RNA) is more stable and accessible in the cell than its tertiary structure, making it essential for functional prediction. Although deep learning has shown promising results in this field,…

Biomolecules · Quantitative Biology 2024-06-21 Cheng Tan , Zhangyang Gao , Hanqun Cao , Xingran Chen , Ge Wang , Lirong Wu , Jun Xia , Jiangbin Zheng , Stan Z. Li

We present an analogue of the differential calculus in which the role of polynomials is played by certain ordered sets and trees. Our combinatorial calculus has all nice features of the usual calculus and has an advantage that the elements…

Combinatorics · Mathematics 2007-08-28 Artur Jez , Piotr Sniady

The paper summarizes the construction of pairings on some standard spectral sequences in algebraic topology.

Algebraic Topology · Mathematics 2007-05-23 Daniel Dugger

We review a derivation of the numbers of RNA complexes of an arbitrary topology. These numbers are encoded in the free energy of the hermitian matrix model with potential V(x)=x^2/2-stx/(1-tx), where s and t are respective generating…

Quantitative Methods · Quantitative Biology 2017-05-23 Jørgen E. Andersen , Leonid O. Chekhov , R. C. Penner , Christian M. Reidys , Piotr Sułkowski

In this paper, we construct some examples of rank-2 Brill-Noether loci with "unexpected" properties on general curves. The key example is in genus 6, but we also have interesting examples in rank 5 and in higher genus. We relate some of our…

Algebraic Geometry · Mathematics 2017-08-08 Peter Newstead

In this first paper, we look at the following question: are the properties of the Fibonacci tree still true if we consider a finitely generated tree by the same rules but rooted at a black node? The direct answer is no, but new properties…

Formal Languages and Automata Theory · Computer Science 2019-04-30 Maurice Margenstern