
Given a sequence $(a_k)=a_0,a_1,a_2,\ldots$ of real numbers, define a new sequence $\mathcal{L}(a_k)=(b_k)$ where $b_k=a_k^2-a_{k-1}a_{k+1}$. So $(a_k)$ is log-concave if and only if $(b_k)$ is a nonnegative sequence. Call $(a_k)$ $\textit{infinitely log-concave}$ if $\mathcal{L}^i(a_k)$ is nonnegative for all $i \geq 1$. Boros and Moll conjectured that the rows of Pascal's triangle are infinitely log-concave. Using a computer and a stronger version of log-concavity, we prove their conjecture for the $n$th row for all $n \leq 1450$. We can also use our methods to give a simple proof of a recent result of Uminsky and Yeats about regions of infinite log-concavity. We investigate related questions about the columns of Pascal's triangle, $q$-analogues, symmetric functions, real-rooted polynomials, and Toeplitz matrices. In addition, we offer several conjectures. Étant donné une suite $(a_k)=a_0,a_1,a_2,\ldots$ de nombres réels, on définit une nouvelle suite $\mathcal{L}(a_k)=(b_k)$ où $b_k=a_k^2-a_{k-1}a_{k+1}$. Alors $(a_k)$ est log-concave si et seulement si $(b_k)$ est une suite non négative. On dit que $(a_k)$ est $\textit{infiniment log-concave}$ si $\mathcal{L}^i(a_k)$ est non négative pour tout $i \geq 1$. Boros et Moll ont conjecturé que les lignes du triangle de Pascal sont infiniment log-concave. Utilisant un ordinateur et une version plus forte de log-concavité, on vérifie leur conjecture pour la $n$ième ligne, pour tout $n \leq 1450$. On peut aussi utiliser nos méthodes pour donner une preuve simple d'un résultat récent de Uminsky et Yeats à propos des régions de log-concavité infini. Reliées à ces idées, on examine des questions à propos des colonnes du triangle de Pascal, des $q$-analogues, des fonctions symétriques, des polynômes avec racines réelles, et des matrices de Toeplitz. De plus, on offre plusieurs conjectures.
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm], binomial coefficients, computer proof, Combinatorial inequalities, infinite log-concavity, toeplitz matrices, QA1-939, Binomial coefficients, FOS: Mathematics, Mathematics - Combinatorics, Iteration theory, iterative and composite equations, symmetric functions, Gaussian polynomial, [math.math-co] mathematics [math]/combinatorics [math.co], real roots, Computer proof, Symmetric functions and generalizations, Basic hypergeometric functions, Applied Mathematics, Infinite log-concavity, gaussian polynomial, Symmetric functions, [MATH.MATH-CO] Mathematics [math]/Combinatorics [math.CO], [INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM], Real roots, \(q\)-calculus and related topics, Toeplitz matrices, Combinatorics (math.CO), Factorials, binomial coefficients, combinatorial functions, Mathematics, 05A10 (Primary) 05A20, 05E05, 39B12 (Secondary)
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm], binomial coefficients, computer proof, Combinatorial inequalities, infinite log-concavity, toeplitz matrices, QA1-939, Binomial coefficients, FOS: Mathematics, Mathematics - Combinatorics, Iteration theory, iterative and composite equations, symmetric functions, Gaussian polynomial, [math.math-co] mathematics [math]/combinatorics [math.co], real roots, Computer proof, Symmetric functions and generalizations, Basic hypergeometric functions, Applied Mathematics, Infinite log-concavity, gaussian polynomial, Symmetric functions, [MATH.MATH-CO] Mathematics [math]/Combinatorics [math.CO], [INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM], Real roots, \(q\)-calculus and related topics, Toeplitz matrices, Combinatorics (math.CO), Factorials, binomial coefficients, combinatorial functions, Mathematics, 05A10 (Primary) 05A20, 05E05, 39B12 (Secondary)
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 23 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
