Zobrazeno 1 - 10
of 423
pro vyhledávání: '"WAGNER, DAVID G."'
The concept of a fully interlacing matrix of formal power series with real coefficients is introduced. This concept extends and strengthens that of an interlacing sequence of real-rooted polynomials with nonnegative coefficients, in the special case
Externí odkaz:
http://arxiv.org/abs/2404.12989
Autor:
Brown, Jason I., Wagner, David G.
While much attention has been directed to the maximum modulus and maximum real part of chromatic roots of graphs of order $n$ (that is, with $n$ vertices), relatively little is known about the maximum imaginary part of such graphs. We prove that the
Externí odkaz:
http://arxiv.org/abs/1706.09093
Publikováno v:
Case Reports in Obstetrics & Gynecology; 10/23/2024, Vol. 2024, p1-4, 4p
Autor:
Gao, Wenbo, Wagner, David G.
We investigate the strong Rayleigh property of matroids for which the basis enumerating polynomial is invariant under a Young subgroup of the symmetric group on the ground set. In general, the Grace-Walsh-Szeg\H{o} theorem can be used to simplify the
Externí odkaz:
http://arxiv.org/abs/1411.7735
Publikováno v:
in Notions of positivity and the geometry of polynomials. Dedicated to the memory of Julius Borcea. Basel: Birkh\"auser. Trends in Mathematics, 63-78 (2011). ISBN 978-3-0348-0141-6/hbk; ISBN 978-3-0348-0142-3/ebook
Let A be an n-by-n matrix of real numbers which are weakly decreasing down each column, Z_n = diag(z_1,..., z_n) a diagonal matrix of indeterminates, and J_n the n-by-n matrix of all ones. We prove that per(J_nZ_n+A) is stable in the z_i, resolving a
Externí odkaz:
http://arxiv.org/abs/1010.2565
Autor:
Wagner, David G.
Univariate polynomials with only real roots -- while special -- do occur often enough that their properties can lead to interesting conclusions in diverse areas. Due mainly to the recent work of two young mathematicians, Julius Borcea and Petter Br\"
Externí odkaz:
http://arxiv.org/abs/0911.3569
Autor:
Su, Yi, Wagner, David G.
For a finite multigraph G, let \Lambda(G) denote the lattice of integer flows of G -- this is a finitely generated free abelian group with an integer-valued positive definite bilinear form. Bacher, de la Harpe, and Nagnibeda show that if G and H are
Externí odkaz:
http://arxiv.org/abs/0908.4071
Autor:
Brändén, Petter, Wagner, David G.
We prove that the symmetrizer of a permutation group preserves stability of a polynomial if and only if the group is orbit homogeneous. A consequence is that the hypothesis of permutation invariance in the Grace-Walsh-Szeg\H{o} Coincidence Theorem ca
Externí odkaz:
http://arxiv.org/abs/0809.3225
Autor:
Wagner, David G.
The Heilmann-Lieb Theorem on (univariate) matching polynomials states that the polynomial $\sum_k m_k(G) y^k$ has only real nonpositive zeros, in which $m_k(G)$ is the number of $k$-edge matchings of a graph $G$. There is a stronger multivariate vers
Externí odkaz:
http://arxiv.org/abs/0803.1659
Autor:
Wagner, David G., Wei, Yehua
We establish a convenient necessary and sufficient condition for a multiaffine real polynomial to be stable, and use it to verify that the half-plane property holds for seven small matroids that resisted the efforts of Choe, Oxley, Sokal, and Wagner
Externí odkaz:
http://arxiv.org/abs/0709.1269