We construct large families of two-dimensional travelling water waves propagating under the influence of gravity in a flow of constant vorticity over a flat bed. A Riemann-Hilbert problem approach is used to recast the governing equations as a one-dimensional elliptic pseudo-differential equation with a scalar constraint. The structural properties of this formulation, which arises as the Euler-...

The purpose of the present paper is to establish the validity of the Euler–Lagrange equation for the solution x̂ to the classical problem of the calculus of variations.  2004 Elsevier Inc. All rights reserved.

This paper investigates virtual holonomic constraints for Euler-Lagrange systems with n degreesof-freedom and n− 1 controls. In our framework, a virtual holonomic constraint is a relation specifying n − 1 configuration variables in terms of a single angular configuration variable. The enforcement by feedback of such a constraint induces a desired repetitive behavior in the system. We give condi...

In this paper, first a class of fractional differential equations are obtained by using the fractional variational principles. We find a fractional Lagrangian L(x(t), where aD α t x(t)) and 0 < α < 1, such that the following is the corresponding Euler-Lagrange tD α b ( c aD α t )x(t) + b(t, x(t))( c aD α t x(t)) + f(t, x(t)) = 0. (1) At last, exact solutions for some Euler-Lagrange equations ar...

This paper addresses the classical and discrete Euler-Lagrange equations for systems of n particles interacting quadratically in R. By highlighting the role played by the center of mass of the particles, we solve the previous systems via the classical quadratic eigenvalue problem (QEP) and its discrete transcendental generalization. The roots of classical and discrete QEP being given, we state ...

to be solved in positive integers x , y for a given nonzero integer d. For example, for d = 5 one can take x = 9, y = 4. We shall always assume that d is positive but not a square, since otherwise there are clearly no solutions. The English mathematician John Pell (1610– 1685) has nothing to do with the equation. Euler (1707–1783) mistakenly attributed to Pell a solution method that had in fact...

Cosmological solutions of gravity coupled to scalar fields, with arbitrary scalar potential, were recently shown to be geodesics in an appropriately augmented, and conformally rescaled, target space. Here we obtain these geodesics as solutions of the Euler-Lagrange equations of a relativistic particle action. As an application, we find some exact (flat and curved) cosmologies for models with N ...

The Euler-Lagrange equations for some class of gravitational actions are calculated by means of Palatini principle. Polynomial structures with Einstein metrics appear among extremals of this variational problem.

The main purpose of this paper is to present a systemic study of some families of multiple q-Euler numbers and polynomials. In particular, by using the q-Volkenborn integration on Zp, we construct p-adic q-Euler numbers and polynomials of higher order. We also define new generating functions of multiple q-Euler numbers and polynomials. Furthermore, we construct Euler q-Zeta function.

Abstract. We study vesicles formed by lipid bilayers that are governed by an elastic bending energy and on which the lipids laterally separate forming two different phases. The energy laden phase interfaces may be modeled as curves on the hyper-surface representing the membrane (sharp interface model). The phase field methodology is another powerful tool to model such phase separation phenomena...