Results 41 to 50 of about 375,845 (279)

Quadratic Discriminant Analysis of Spatially Correlated Data

Nonlinear Analysis, 2001
The problem of classification of the realisation of the stationary univariate Gaussian random field into one of two populations with different means and different factorised covariance matrices is considered. In such a case optimal classification rule in
K. Dučinskas, J. Šaltytė
doaj   +1 more source

Naturalness and Chaotic Inflation in Supergravity from Massive Vector Multiplets

, 2014
We study the embedding of the quadratic model of chaotic inflation into the 4D, N=1 minimal theories of supergravity by the use of massive vector multiplets and investigate its robustness against higher order corrections.
Farakos, Fotis, von Unge, Rikard
core   +1 more source

Polynomial first integrals of quadratic vector fields

Journal of Differential Equations, 2006
The goal of this paper is to characterize those quadratic differential equations in the plane having a polynomial first integral, and to provide an explicit expression of these systems as well as of their polynomial first integrals. It is well known that if the system writes as \[ \dot x=P(x,y), \quad \dot y=Q(x,y) \] it is not restrictive to assume ...
Chavarriga, Javier, García, Belén, Llibre, Jaume, del Río, Jesús S. Pérez, Rodríguez, José Angel   +4 more
openaire   +2 more sources

Quadratic Morse-Smale Vector Fields which are not Structurally Stable [PDF]

Proceedings of the American Mathematical Society, 1982
An example is given of a quadratic system in the plane which is Morse-Smale but not structurally stable. Also, it is proved that no such example exists for a quadratic system which is a gradient.
Chicone, Carmen, Shafer, Douglas S.
openaire   +1 more source

Generalized spinning particles on $${\mathcal {S}}^2$$ S 2 in accord with the Bianchi classification

European Physical Journal C: Particles and Fields, 2021
Motivated by recent studies of superconformal mechanics extended by spin degrees of freedom, we construct minimally superintegrable models of generalized spinning particles on $${\mathcal {S}}^2$$ S 2 , the internal degrees of freedom of which are ...
Anton Galajinsky
doaj   +1 more source

Gravitomagnetic Moments of the Fundamental Fields

, 1998
The quadratic form of the Dirac equation in a Riemann spacetime yields a gravitational gyromagnetic ratio \kappa_S = 2 for the interaction of a Dirac spinor with curvature. A gravitational gyromagnetic ratio \kappa_S = 1 is also found for the interaction
J. G. PEREIRA, Khriplovich I. B., R. ALDROVANDI, V. C. DE ANDRADE   +3 more
core   +2 more sources

An Extended Newmark-FDTD Method for Complex Dispersive Media

International Journal of Antennas and Propagation, 2018
Based on polarizability in the form of a complex quadratic rational function, a novel finite-difference time-domain (FDTD) approach combined with the Newmark algorithm is presented for dealing with a complex dispersive medium.
Yu-Qiang Zhang, Peng-Ju Yang
doaj   +1 more source

Poincare gauge theory of gravity: Friedman cosmology with even and odd parity modes. Analytic part

, 2010
We propose a cosmological model in the framework of the Poincar\'e gauge theory of gravity (PG). The gravitational Lagrangian is quadratic in curvature and torsion.
A. Trautman, A. C. Hearn, B. Kuchowicz, B. Kuchowicz, C. Kiefer, C. Mukku, C. Rovelli, D. W. Sciama, E. Schrüfer, E. W. Mielke, F. Halbwachs, F. W. Hehl, F. W. Hehl, Friedrich W. Hehl, H. Chen, J. A. Schouten, J. M. Nester, James M. Nester, K. Hayashi, K. Hayashi, L. Ryder, M. Blagojević, M. S. Sozzi, P. Baekler, P. A. M. Dirac, Peter Baekler, T. Frankel, T. Ortín, Y. N. Obukhov, É. Cartan   +29 more
core   +1 more source

Phase Field Failure Modeling: Brittle‐Ductile Dual‐Phase Microstructures under Compressive Loading

Advanced Engineering Materials, EarlyView.
The approach by Amor and the approach by Miehe and Zhang for asymmetric damage behavior in the phase field method for fracture are compared regarding their fitness for microcrack‐based failure modeling. The comparison is performed for the case of a dual‐phase microstructure with a brittle and a ductile constituent.
Jakob Huber, Jan Torgersen, Ewald Werner
wiley   +1 more source

Parameter Constraints and Real Structures in Quadratic Semicomplete Vector Fields on C3

International Journal of Mathematics and Mathematical Sciences
It is a remarkable fact that among the known examples of quadratic semicomplete vector fields on C3, it is always possible to find linear coordinates where the corresponding vector field has all—or “almost all”—coefficients in the real numbers.
Daniel de la Rosa Gómez
doaj   +1 more source