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The present paper is exclusively devoted to counterexamples about commutators and self commutators of unbounded operators on a Hilbert space. As a bonus, we provide a simpler counterexample than McIntosh's famous example obtained some while…

Functional Analysis · Mathematics 2018-11-27 Mohammed Hichem Mortad

Several results about the union-closed sets conjecture are presented.

Combinatorics · Mathematics 2017-06-21 Yining Hu

Let $C$ be an irreducible algebraic curve defined over a number field and inside an algebraic torus of dimension at least 3. We partially answer a question posed by Levin on points on $C$ for which a non-trivial power lies again on $C$. Our…

Number Theory · Mathematics 2015-04-23 Martin Bays , Philipp Habegger

A precise tie between a univariate spline's knots and its zeros abundance and dissemination is formulated. As an application, a conjecture formulated by De Concini and Procesi is shown to be true in the special univariate, unimodular case.…

Numerical Analysis · Mathematics 2008-10-16 Marco Caminati

We study the postulation of a general union $X\subset \mathbb {P}^3$ of one m-point $mP$ and $t$ disjoint lines. We prove that it has the expected Hilbert function, proving a conjecture by E. Carlini, M. V. Catalisano and A. V. Geramita.

Algebraic Geometry · Mathematics 2014-05-02 E. Ballico

I expound here in a more detailed way a proof of an important Serini's theorem, which I have already sketched in a previous Note. Two related questions are briefly discussed.

General Physics · Physics 2007-05-23 A. Loinger

Motivated by various equivalent versions of the SHGH conjecture for $\mathbb{P}^2$ blown up at very general points, we propose a similar conjecture for Hirzebruch surfaces. We prove that this conjecture is true for the Hirzebruch surface…

Algebraic Geometry · Mathematics 2026-01-30 Cyril J. Jacob , Ronnie Sebastian

For a Latt\`es map $\phi:\mathbb P^1 \to \mathbb P^1$ defined over a number field $K$, we prove a conjecture on the integrality of points in the backward orbit of $P\in \mathbb P^1(\overline K)$ under $\phi$.

Number Theory · Mathematics 2015-08-26 Vijay A. Sookdeo

In this paper, we give some results on the number of meromorphic mappings of C^m into P^n under a condition on the inverse images of hyperplanes in P^n. At the same time, we give an answer for an open question by H.Fujimoto.

Complex Variables · Mathematics 2014-12-01 Gerd Dethloff , Tran Van Tan

In this short note we give counterexamples to several results related to extension theorems published recently.

Functional Analysis · Mathematics 2013-03-19 Constantin Zalinescu

Nous rappelons l'historique de la demonstration de la conjecture des fibres de Seifert, ainsi que ses motivations et ses diverses generalisations. ----- We recall the history of the proof of the Seibert fiber space conjecture, as well as…

Algebraic Topology · Mathematics 2007-05-23 Jean-Philippe Preaux

We put a new conjecture on primes from the point of view of its binary expansions and make a step towards justification.

Number Theory · Mathematics 2007-06-11 Vladimir Shevelev

In this short note we report on results on a computational search for a counterexample to the strong coincidence conjecture. In particular, we discuss the method used so that further searches can be conducted.

Dynamical Systems · Mathematics 2017-06-19 Scott Balchin

We study the global existence issue for a three-dimensional Approximate Deconvolution Model with a vertical filter. We consider this model in a bounded cylindrical domain where we construct a unique global weak solution. The proof is based…

Analysis of PDEs · Mathematics 2013-01-21 Hani Ali

In the paper we prove Harbourne-Hirschowitz conjecture for quasi-homogeneous linear systems on $\mathbb P^2$ for $m=7$, 8, 9, 10, i.e. systems of curves of given degree passing through points in general position with multiplicities at least…

Algebraic Geometry · Mathematics 2008-04-09 Marcin Dumnicki

Let $p$ be an odd prime and $S$ a nonabelian finite $p$-group. In [9, 10], they proposed the following conjecture: if $\mathcal{F}$ be a transitive fusion system over a finite $p$-group $S$, then $S$ is either extraspecial of order $p^{3}$…

Group Theory · Mathematics 2024-12-05 Rui Gao , Heguo Liu , Xingzhong Xu , Sheng Yang

In this paper, we study a general Syracuse problem. We give some necessary conditions concerning the existence of eventual non trivial cycles. Some properties based on linear logarithmic forms are established. New general conjectures are…

Number Theory · Mathematics 2021-09-01 Abderrahman Bouhamidi

We formulate a precise conjecture that, if true, extends the converse theorem of Hecke without requiring hypotheses on twists by Dirichlet characters or an Euler product. The main idea is to linearize the Euler product, replacing it by…

It is demonstrated how the software system polymake can be used for computations in toric geometry. More precisely, counter-examples to conjectures related to A-determinants and defect polytopes are constructed.

Combinatorics · Mathematics 2011-05-26 Michael Joswig , Andreas Paffenholz

We present an approach to Fuglede's conjecture in $\mathbb{Z}_p^3$ using linear programming bounds, obtaining the following partial result: if $A\subseteq\mathbb{Z}_p^3$ with $p^2-p\sqrt{p}+\sqrt{p}<|A|<p^2$, then $A$ is not spectral.

Classical Analysis and ODEs · Mathematics 2022-12-29 Romanos Diogenes Malikiosis