Results 31 to 40 of about 679,323 (292)

Systems of quadratic forms.

Journal für die reine und angewandte Mathematik (Crelles Journal), 1984
Let \(u_ F(r)\) be the smallest integer such that every system of r quadratic forms in n variables, defined over a field F, has a nontrivial common zero if \(n>u_ F(r)\). Let \(u_ F(r)=\infty\) if no such integer exists. Then \(u_ F(r)\leq frac{1}{2}(r^ 2+r)u_ F(1)\) and there exist fields for which this bound is best possible when \(r=1,2,3\). If F is
openaire   +2 more sources

Rigid Polynomial Differential Systems with Homogeneous Nonlinearities

Mathematics
Planar differential systems whose angular velocity is constant are called rigid or uniform differential systems. The first rigid system goes back to the pendulum clock of Christiaan Huygens in 1656; since then, the interest for the rigid systems has been
Jaume Llibre
doaj   +1 more source

Quadratic pseudosupersymmetry in two-level systems

, 2005
Using the intertwining relation we construct a pseudosuperpartner for a (non-Hermitian) Dirac-like Hamiltonian describing a two-level system interacting in the rotating wave approximation with the electric component of an electromagnetic field.
Bagchi B Banerjee A Caliceti E Cannata F Geyer H B Quesne C Znojil M, Bagchi B Bíla H Jakubský V Mallik S Quesne C Znojil M, Bagrov V G, Bagrov V G Baldiotti M C Gitman D M Shamshutdinova V V, Baz' A I, Bender C M, Boris F Samsonov, Dorey P, Golfand Y A, Keldysh M V, Levai G, Marchenko V A, Naimark M A, Orszag M, Ramírez A, Rosas-Ortiz O, Ruschhaupt A, Samsonov B F, Samsonov B F, V V Shamshutdinova, Znojil M Gazeau J-P Kerner R Antoine J-P Metens S Thibon J-Y   +20 more
core   +2 more sources

Subelliptic Estimates for Overdetermined Systems of Quadratic Differential Operators [PDF]

, 2010
We prove global subelliptic estimates for systems of quadratic differential operators. Quadratic differential operators are operators defined in the Weyl quantization by complex-valued quadratic symbols.
Pravda-Starov, Karel
core   +1 more source

Sequence determinants of RNA G‐quadruplex unfolding by Arg‐rich regions

FEBS Letters, EarlyView.
We show that Arg‐rich peptides selectively unfold RNA G‐quadruplexes, but not RNA stem‐loops or DNA/RNA duplexes. This length‐dependent activity is inhibited by acidic residues and is conserved among SR and SR‐related proteins (SRSF1, SRSF3, SRSF9, U1‐70K, and U2AF1).
Naiduwadura Ivon Upekala De Silva, Puspa Kunwar, Md Ibnul Rifat Rahman, Joanna Koryo Kwao, Nathan Lehman, Zihan Zhang, Trenton Paul, Claire Cheng, Nicholas Truex, Hui‐Ting Lee, Jun Zhang   +10 more
wiley   +1 more source

Quadratic systems with two invariant real straight lines and an invariant parabola

Electronic Journal of Qualitative Theory of Differential Equations
After the linear differential systems in the plane the easiest ones are the quadratic polynomial differential systems. Due to their nonlinearity and also to their many applications these systems have been studied by many authors. Let QS denote the set of
Jaume Llibre, Huaxin Ou
doaj   +1 more source

Global configurations of singularities for quadratic differential systems with exactly three finite singularities of total multiplicity four

Electronic Journal of Qualitative Theory of Differential Equations, 2015
In this article we obtain the geometric classification of singularities, finite and infinite, for the two subclasses of quadratic differential systems with total finite multiplicity $m_f=4$ possessing exactly three finite singularities, namely: systems ...
Joan Artés, Jaume Llibre, Dana Schlomiuk, Nicolae Vulpe   +3 more
doaj   +1 more source

Integrable Hamiltonian systems with vector potentials

, 2004
We investigate integrable 2-dimensional Hamiltonian systems with scalar and vector potentials, admitting second invariants which are linear or quadratic in the momenta.
Darboux G., Giuseppe Pucacco, Kjell Rosquist, Pucacco G., Whittaker E. T.   +4 more
core   +1 more source

Configuration of separability and tests for multipartite entanglement in Bell-type experiments [PDF]

, 2002
We derive tight quadratic inequalities for all kinds of hybrid separable-inseparable $n$-particle density operators on an arbitrary dimensional space. This methodology enables us to truly derive a tight quadratic inequality as tests for full $n$-partite ...
A. V. Belinskii, D. M. Greenberger, Koji Nagata, Masato Koashi, Nobuyuki Imoto   +4 more
core   +2 more sources

LDAcoop: Integrating non‐linear population dynamics into the analysis of clonogenic growth in vitro

Molecular Oncology, EarlyView.
Limiting dilution assays (LDAs) quantify clonogenic growth by seeding serial dilutions of cells and scoring wells for colony formation. The fraction of negative wells is plotted against cells seeded and analyzed using the non‐linear modeling of LDAcoop.
Nikko Brix, Daniel Samaga, Katharina Gehr, Benedek Dankó, Mohamed Schumann, Guido Drexler, Ahmed Alnatsha, Georg Beyer, Ujjwal Mahajan, Martin Selmansberger, Julia Mayerle, Claus Belka, Horst Zitzelsberger, Kirsten Lauber   +13 more
wiley   +1 more source