A quaternionic partial differential equation is shown to be a generalisation of the traditional Riccati equation and its relationship with the Schrödinger equation is established. Various approaches to the problem of finding particular solutions to this equation are explored, and the generalisations of two theorems of Euler on the Riccati equation, which correspond to this partial differential ...

We prove Euler-Lagrange fractional equations and sufficient optimality conditions for problems of the calculus of variations with functionals containing both fractional derivatives and fractional integrals in the sense of Riemann-Liouville.

. Consider a mechanical system consisting of N particles in R subject to some forces. Let xi ∈ R denote the position vector of the ith particle. Then all possible positions of the system are described by N -tuples (x1, . . . , xN ) ∈ (R) . The space (R) is an example of a configuration space. The time evolution of the system is described by a curve (x1(t), . . . , xN (t)) in (R) and is governed...

Let M be a Kähler surface and Σ be a closed symplectic surface which is smoothly immersed in M . Let α be the Kähler angle of Σ in M . We first deduce the Euler-Lagrange equation of the functional L = ∫ Σ 1 cosα dμ in the class of symplectic surfaces. It is cos αH = (J(J∇ cosα)), where H is the mean curvature vector of Σ in M , J is the complex structure compatible with the Kähler form ω in M ,...

In this paper we investigate the following question: under what conditions can a second-order homogeneous ordinary differential equation (spray) be the geodesic equation of a Finsler space. We show that the EulerLagrange partial differential system on the energy function can be reduced to a first order system on this same function. In this way we are able to give effective necessary and suffici...

In this manuscript we are interested in stored energy functionals W defined on the set of d × d matrices, which not only fail to be convex but satisfy limdet ξ→0+ W (ξ) = ∞. We initiate a study which we hope would lead to a theory for the existence and uniqueness of minimizers of functionals of the form E(u) = ∫ Ω (W (∇u) − F · u)dx, as well as their Euler–Lagrange equations. The techniques dev...

The equations of motion of multibody systems with holonomic constraints are of index 3 and therefore not directly solvable by standard ODE or DAE methods. Until now, a number of regularization methods have been proposed to treat these systems [1, 2, 3, 4], but as they are based on different points of view they have never been compared with respect to their physical properties, invariance under ...

Using a differential geometric treatment, we analytically derived the expression for De Sitter geodesic precession in the elliptical motion of the Earth through the gravitational field of the Sun with Schwarzschild’s metric. The expression obtained in this paper in a simple way, using a classical approach, agrees with that given in B. M. Barker and R. F. O’Connell 1970, 1975 in a different sett...

We prove the following results: (1) A unique smooth solution exists for short time for the heat equation associated with the MM obius energy of loops in a euclidean space, starting with any simple smooth loop. (2) A critical loop of the energy is smooth if it has cube-integrable curvature. Combining this with an earlier result of M. Freedman, Z. Wang and the author, any local minimizer of the e...

Area-proportional Euler diagrams have many applications, for example they are often used for visualizing data in medical and biological domains. There have been a number of recent research efforts to automatically draw Euler diagrams when the areas of the regions are not considered, leading to a range of different drawing techniques. By contrast, substantially less progress has been made on the...