Results 11 to 20 of about 2,717 (82)

String Theory - From Physics to Metaphysics [PDF]

, 2006
Currently, string theory represents the only advanced approach to a unification of all interactions, including gravity. In spite of the more than thirty years of its existence it did not make any empirically testable predictions.
Hedrich, Reiner
core   +3 more sources

Periodic perturbations of quadratic planar polynomial vector fields

Anais da Academia Brasileira de Ciências, 2002
In this work are studied periodic perturbations, depending on two parameters, of quadratic planar polynomial vector fields having an infinite heteroclinic cycle, which is an unbounded solution joining two saddle points at infinity.
MARCELO MESSIAS
doaj   +1 more source

Mathematical analysis of an economic growth model with perfect-substitution technologies

Nonlinear Analysis, 2020
The purpose of this paper is to highlight certain features of a dynamic optimisation problem in an economic growth model with environmental negative externalities that gives rise to a two-dimensional dynamical system.
Paolo Russu
doaj   +1 more source

Rankin-Selberg methods for closed strings on orbifolds [PDF]

, 2013
In recent work we have developed a new unfolding method for computing one-loop modular integrals in string theory involving the Narain partition function and, possibly, a weak almost holomorphic elliptic genus. Unlike the traditional approach, the Narain
Angelantonj, Carlo, Florakis, Ioannis, Pioline, Boris   +2 more
core   +4 more sources

First integrals and phase portraits of planar polynomial differential cubic systems with invariant straight lines of total multiplicity eight

Electronic Journal of Qualitative Theory of Differential Equations, 2017
In the article [C. Bujac, J. Llibre, N. Vulpe, Qual. Theory Dyn. Syst. 15(2016), 327–348] for the family of cubic differential systems with the maximum number of invariant straight lines, i.e.
Cristina Bujac, Nicolae Vulpe
doaj   +1 more source

The Lambrechts-Stanley Model of Configuration Spaces [PDF]

, 2018
We prove the validity over $\mathbb{R}$ of a commutative differential graded algebra model of configuration spaces for simply connected closed smooth manifolds, answering a conjecture of Lambrechts--Stanley. We get as a result that the real homotopy type
Idrissi, Najib
core   +3 more sources

Large amplitude oscillations for a class of symmetric polynomial differential systems in R³

Anais da Academia Brasileira de Ciências, 2007
In this paper we study a class of symmetric polynomial differential systems in R³, which has a set of parallel invariant straight lines, forming degenerate heteroclinic cycles, which have their two singular endpoints at infinity.
Jaume Llibre, Marcelo Messias
doaj   +1 more source

Intersection Theory on Linear Subvarieties of Toric Varieties [PDF]

, 2016
We give a complete description of the cohomology ring $A^*(\overline Z)$ of a compactification of a linear subvariety $Z$ of a torus in a smooth toric variety whose fan $\Sigma$ is supported on the tropicalization of $Z$.
Gross, Andreas
core   +1 more source

BPS invariants of semi-stable sheaves on rational surfaces [PDF]

, 2013
BPS invariants are computed, capturing topological invariants of moduli spaces of semi-stable sheaves on rational surfaces. For a suitable stability condition, it is proposed that the generating function of BPS invariants of a Hirzebruch surface takes ...
Manschot, Jan
core   +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