Stability of Kronecker coefficients via discrete tomography

In this paper we give a new sufficient condition for a general stability of Kronecker coefficients, which we call it additive stability. It was motivated by a recent talk of J. Stembridge at the conference in honor of Richard P. Stanley's 70th birthday, and it is based on work of the author on discrete tomography along the years. The main contribution of this paper is the discovery of the connection between additivity of integer matrices and stability of Kronecker coefficients. Additivity, in our context, is a concept from discrete tomography. Its advantage is that it is very easy to produce lots of examples of additive matrices and therefore of new instances of stability properties. We also show that Stembridge's hypothesis and additivity are closely related, and prove that all stability properties of Kronecker coefficients discovered before fit into additive stability.Comment: 22 page

Heavy quark asymmetries with DELPHI

The measurements of the forward-backward asymmetry in Z -> c cbar and Z -> b bbar decays are among the most precise determinations of sin^2(theta)_W. In this paper the results obtained by the DELPHI experiment at LEP with three different analyses are reviewed together with the impact of the combined LEP result on the global Electroweak fit.Comment: 7 pages, RevTeX, fonts changed in 2 eps file

Spectral Scaling in Complex Networks

A complex network is said to show topological isotropy if the topological structure around a particular node looks the same in all directions of the whole network. Topologically anisotropic networks are those where the local neighborhood around a node is not reproduced at large scale for the whole network. The existence of topological isotropy is investigated by the existence of a power-law scaling between a local and a global topological characteristic of complex networks obtained from graph spectra. We investigate this structural characteristic of complex networks and its consequences for 32 real-world networks representing informational, technological, biological, social and ecological systems.Comment: 9 pages, 3 figure

Structural patterns in complex networks through spectral analysis

The study of some structural properties of networks is introduced from a graph spectral perspective. First, subgraph centrality of nodes is defined and used to classify essential proteins in a proteomic map. This index is then used to produce a method that allows the identification of superhomogeneous networks. At the same time this method classify non-homogeneous network into three universal classes of structure. We give examples of these classes from networks in different real-world scenarios. Finally, a communicability function is studied and showed as an alternative for defining communities in complex networks. Using this approach a community is unambiguously defined and an algorithm for its identification is proposed and exemplified in a real-world network

Communicability in temporal networks

A first-principles approach to quantify the communicability between pairs of nodes in temporal networks is proposed. It corresponds to the imaginary-time propagator of a quantum random walk in the temporal network, which accounts for unique structural and temporal characteristics of both streaming and nonstreaming temporal networks. The influence of the system's temperature on the perdurability of information and how the communicability identifies patterns of communication hidden in the temporal and topological structure of the networks are also studied for synthetic and real-world systems

Isotropization of non-diagonal Bianchi I spacetimes with collisionless matter at late times assuming small data

Assuming that the space-time is close to isotropic in the sense that the shear parameter is small and that the maximal velocity of the particles is bounded, we have been able to show that for non-diagonal Bianchi I-symmetric spacetimes with collisionless matter the asymptotic behaviour at late times is close to the special case of dust. We also have been able to show that all the Kasner exponents converge to 1/3 and an asymptotic expression for the induced metric has been obtained. The key was a bootstrap argument.Comment: V3 18 p. 3 fig. typos corrected, conclusions part extended, references added. To appear in Classical and Quantum Gravit