Results 61 to 70 of about 629,413 (279)
Weak Liouville-Arnol′d Theorems and Their Implications [PDF]
This paper studies the existence of invariant smooth Lagrangian graphs for Tonelli Hamiltonian systems with symmetries. In particular, we consider Tonelli Hamiltonians with n independent but not necessarily involutive constants of motion and obtain two theorems reminiscent of the Liouville-Arnold theorem.
Butler, L. T, SORRENTINO, ALFONSO
openaire +4 more sources
ABSTRACT Liénard equations are analyzed using the recent theory of 𝒞∞‐structures. For each Liénard equation, a 𝒞∞‐structure is determined by using a Lie point symmetry and a 𝒞∞‐symmetry. Based on this approach, a novel method for integrating these equations is proposed, which consists in solving sequentially two completely integrable Pfaffian equations.
Beltrán de la Flor +2 more
wiley +1 more source
On Holditch and Liouville theorems
The authors examine the relationship between the Liouville theorem in mechanics and the Holditch theorem in geometry. They first start by introducing well-known results of Hamiltonian mechanics when the Hamiltonian comes from a Riemannian metric \[ ds^2=g_{ij}dx^idx^j \] on the configuration space. In particular, the authors prove that the solutions of
Hacisalihoǧlu, H. H., Amirov, A. Kh.
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Temporal pulse shaping aspects of refractive X‐ray lenses
This work investigates the temporal effects of refractive X‐ray lenses on ultra‐short pulses from X‐ray free‐electron lasers. Using both a full Fresnel theory model and a simplified ray‐tracing approach, the paper analyzes the pulse elongation and spatio‐temporal distortions introduced by these focusing optics.Refractive X‐ray lenses are frequently ...
Fabian Trost +2 more
wiley +1 more source
Sharp Gradient Estimate and Yau's Liouville Theorem for the Heat Equation on Noncompact Manifolds [PDF]
We derive a sharp, localized version of elliptic type gradient estimates for positive solutions (bounded or not) to the heat equation. These estimates are related to the Cheng–Yau estimate for the Laplace equation and Hamilton's estimate for bounded ...
P. Souplet, Qi S. Zhang
semanticscholar +1 more source
Curves of best approximation on wonderful varieties
Abstract We give an unconditional proof of the Coba conjecture for wonderful compactifications of adjoint type for semisimple Lie groups of type An$A_n$. We also give a proof of a slightly weaker conjecture for wonderful compactifications of adjoint type for arbitrary Lie groups.
Christopher Manon +2 more
wiley +1 more source
Dimer models and conformal structures
Abstract Dimer models have been the focus of intense research efforts over the last years. Our paper grew out of an effort to develop new methods to study minimizers or the asymptotic height functions of general dimer models and the geometry of their frozen boundaries.
Kari Astala +3 more
wiley +1 more source
Under different criteria, we prove the existence of solutions for sequential fractional differential inclusions containing Riemann–Liouville and Caputo type derivatives and supplemented with generalized fractional integral boundary conditions.
Jessada Tariboon +3 more
doaj +1 more source
Cazenave‐Dickstein‐Weissler‐Type Extension of Fujita'S Problem on Heisenberg Groups
ABSTRACT This paper investigates the Fujita critical exponent for a heat equation with nonlinear memory posed on the Heisenberg groups. A sharp threshold is identified such that, for exponent values less than or equal to this critical value, no global solution exists, regardless of the choice of nonnegative initial data. Conversely, for exponent values
Mokhtar Kirane +3 more
wiley +1 more source
ABSTRACT This paper investigates the generalized Hyers–Ulam stability of the Laplace equation subject to Neumann boundary conditions in the upper half‐space. Traditionally, Hyers–Ulam stability problems for differential equations are analyzed by examining the system's error, particularly in relation to a forcing term.
Dongseung Kang +2 more
wiley +1 more source

