Autor(es)

Dimitrov, Dimitar K. ^[1] ; Lucas, Fabio R. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, IBILCE, Dept Ciencias Computacao & Estat, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

^[2] Univ Estadual Campinas, IMECC, Dept Matemat Aplicada, BR-13083859 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Proceedings of the American Mathematical Society; v. 139, n. 3, p. 1013-1022, MAR 2011.
• Citações Web of Science: 7

Resumo

The simplest necessary conditions for an entire function psi(x) = Sigma(infinity)(k=0) gamma k xk/k! to be in the Laguerre-Polya class are the Turan inequalities gamma(2)(k) - gamma k+1 gamma k-1 >= 0. These are in fact necessary and sufficient conditions for the second degree generalized Jensen polynomials associated with psi to be hyperbolic. The higher order Turan inequalities 4(gamma(2)(n) - gamma n-1 gamma n+1)(gamma(2)(n+1), - gamma n gamma n+2) - (gamma n gamma n+1 - gamma n-1 gamma n+2)(2) >= 0 are also necessary conditions for a function of the above form to belong to the Laguerre-Polya class. In fact, these two sets of inequalities guarantee that the third degree generalized Jensen polynomials are hyperbolic. Polya conjectured in 1927 and Csordas, Norfolk and Varga proved in 1986 that the Turan inequalities hold for the coefficients of the Riemann xi-function. In this short paper, we prove that the higher order Turan inequalities also hold for the xi-function, establishing the hyperbolicity of the associated generalized Jensen polynomials of degree three. (AU)

• Processo FAPESP: 03/01874-2 - Polinômios ortogonais e similares: propriedades e aplicações
• Beneficiário: Alagacone Sri Ranga
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 06/60420-0 - Zeros de polinômios e de funções inteiras
• Beneficiário: Fábio Rodrigues Lucas
• Modalidade de apoio: Bolsas no Brasil - Doutorado