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We present an elementary proof of a conjecture by I. Ra\c{s}a which is an inequality involving Bernstein basis polynomials and convex functions. It was affirmed in positive very recently by the use of stochastic convex orderings. Moreover,…

Classical Analysis and ODEs · Mathematics 2016-09-02 Ulrich Abel

A conjecture of Berkovich asserts that every non-simple finite p-group has a non-inner automorphism of order p. This conjecture is far from being proved despite the great effort devoted to it. In this paper we prove it for p-groups of…

Group Theory · Mathematics 2013-01-03 Yassine Guerboussa , Miloud Reguiat

We discuss some surprising phenomena from basic calculus related to oscillating functions and to the theorem on the differentiability of inverse functions. Among other things, we see that a continuously differentiable function with a strict…

History and Overview · Mathematics 2016-09-29 Juergen Grahl , Shahar Nevo

All counterexamples of Pinchuk type to the strong real Jacobian conjecture are shown to have rational function field extensions of degree six with no nontrivial automorphisms.

Algebraic Geometry · Mathematics 2013-11-18 L. Andrew Campbell

We construct a finite-dimensional algebra derived equivalent to the example of Kershaw--Rickard. For the Kershaw--Rickard example the delooping level and the sub-derived delooping level are both infinite, while for our algebra both…

Representation Theory · Mathematics 2026-03-16 Liang Chen

In this short note we present a simple counterexample to a nonlinear version of the Krein-Rutman theorem reported in [Nonlinear Anal. 11 (2007), 3084-3090]. Correct versions of this theorem, and related results for superadditive maps are…

Functional Analysis · Mathematics 2019-03-20 Ari Arapostathis

We present an analogue of G\"{o}del's second incompleteness theorem for systems of second-order arithmetic. Whereas G\"{o}del showed that sufficiently strong theories that are $\Pi^0_1$-sound and $\Sigma^0_1$-definable do not prove their…

Logic · Mathematics 2022-09-21 James Walsh

In Mathematical Programming 2003, Gomory and Johnson conjecture that the facets of the infinite group problem are always generated by piecewise linear functions. In this paper we give an example showing that the Gomory-Johnson conjecture is…

Optimization and Control · Mathematics 2017-01-25 Amitabh Basu , Michele Conforti , Gerard Cornuejols , Giacomo Zambelli

Let R be a Gorenstein local domain of dimension one. We show that a nonfree maximal Cohen--Macaulay R-module M possessing more than one nonfree indecomposable summand in the middle term of the almost split sequence ending in M has a…

Commutative Algebra · Mathematics 2019-11-12 Toshinori Kobayashi

In this paper we prove that no consistent finitely axiomatized theory one-dimensionally interprets its own extension with predicative comprehension. This constitutes a result with the flavor of the Second Incompleteness Theorem whose…

Logic · Mathematics 2021-09-07 Fedor Pakhomov , Albert Visser

Recently, G. Mason has produced a counterexample of order 128 to a conjecture in conformal field theory and tensor category theory in [Ma]. Here we easily produce an infinite family of counterexamples, the smallest of which has order 72.

Representation Theory · Mathematics 2019-10-24 J. Miquel Martínez

We present examples of holomorphic functions that vanish to in- finite order at points at the boundary of their domain of definition. They give rise to examples of Dirichlet minimizing Q-valued functions indicating that "higher"-regularity…

Analysis of PDEs · Mathematics 2017-12-21 Jonas Hirsch

We consider counterfactual explanations, the problem of minimally adjusting features in a source input instance so that it is classified as a target class under a given classifier. This has become a topic of recent interest as a way to…

Machine Learning · Computer Science 2021-03-02 Miguel Á. Carreira-Perpiñán , Suryabhan Singh Hada

The $P$ versus $NP$ problem is still unsolved. But there are several oracles with $P$ unequal $NP$ relative to them. Here we will prove, that $P\not=NP$ relative to a $P$-complete oracle. In this paper, we use padding arguments as the proof…

Computational Complexity · Computer Science 2023-05-04 Reiner Czerwinski

We look at an old conjecture of A. Tarski on cardinal arithmetic and show that if a counterexample exists, then there exists one of length omega_1 + omega .

Logic · Mathematics 2009-09-25 Thomas Jech , Saharon Shelah

I give a counter example of function field over GF(2) of genus 4 with class number one. This result contradicts a previous result in [2], Section 2 so that proof is wrong.

Number Theory · Mathematics 2013-11-26 Claudio Stirpe

We present a counterexample to Conjecture~14.1.6 from [Vladimir Kanovei, Borel equivalence relations], regarding Borel equivalence relations on product spaces.

Logic · Mathematics 2025-05-06 Assaf Shani

For classical Bernoulli convolutions, the Rajchman property, i.e. the convergence to zero at infinity of the Fourier transform, was characterized by successive works of Erd{\"o}s [2] and Salem [12]. We prove weak forms of their results for…

Dynamical Systems · Mathematics 2020-12-14 Julien Brémont

We give here a counter-example to a conjecture of Spivakovsky. M. Spivakovsky conjectured that the function that appears in the strong Artin approximation theorem is bounded by a linear function. First we show that there is no Liouville…

Commutative Algebra · Mathematics 2007-05-23 Guillaume Rond

The Neggers-Stanley conjecture (also known as the Poset conjecture) asserts that the polynomial counting the linear extensions of a partially ordered set on $\{1,2,...,p\}$ by their number of descents has real zeros only. We provide…

Combinatorics · Mathematics 2012-04-18 Petter Brändén