We consider a broad class of linear boundary-value problems for systems m ordinary differential equations order r known as general problems. Their solutions y : [a, b] → ℂm belong to the Sobolev space $$ {\left({W}_1^r\right)}^m and boundary conditions are given in form By = q, where B: (C(r−1))m ℂrm is an arbitrary continuous operator. For this problem, we prove that its solution can be approx...

A new method due to Fokas for explicitly solving boundary-value problems for linear partial differential equations is extended to equations with mixed partial derivatives. The Benjamin-Bona-Mahony equation is used as an example: we consider the Robin problem for this equation posed both on the half line and on the finite interval. For specific cases of the Robin boundary conditions the boundary...

This paper presents an optimal solver for the Morley element problem for the boundaryvalue problem of the biharmonic equation by decomposing it into several subproblems and solving these subproblems optimally. The optimality of the proposed method is mathematically proved for general shape-regular grids. Mathematics subject classification: 65F08, 65N30, 65N99

We study the existence of positive solutions for the boundaryvalue problem of the singular higher-order functional differential equation (Ly(n−2))(t) + h(t)f(t, yt) = 0, for t ∈ [0, 1], y(0) = 0, 0 ≤ i ≤ n− 3, αy(n−2)(t)− βy(n−1)(t) = η(t), for t ∈ [−τ, 0], γy(n−2)(t) + δy(n−1)(t) = ξ(t), for t ∈ [1, 1 + a], where Ly := −(py′)′ + qy, p ∈ C([0, 1], (0,+∞)), and q ∈ C([0, 1], [0,+∞)). Our main to...

In the present work, the symmetrized sequential-parallel decomposition method with the fourth order accuracy for the solution of Cauchy abstract problem with an operator under a split form is presented. The fourth order accuracy is reached by introducing a complex coefficient with the positive real part. For the considered scheme, the explicit a priori estimate is obtained. Mathematics Subject ...

We study a semilinear fourth order elliptic problem with exponential nonlinearity. Motivated by a question raised in [Li], we partially extend known results for the corresponding second order problem. Several new difficulties arise and many problems still remain to be solved. We list the ones we feel particularly interesting in the final section. Mathematics Subject Classification: 35J65; 35J40.

Keywords: Difference equations Boundary value problems Symmetric Green's function Fixed points Fourth-order Discrete Beam Lidstone Semipositone a b s t r a c t Various existence, multiplicity, and nonexistence results for nontrivial solutions to a non-linear discrete fourth-order Lidstone boundary value problem with dependence on two parameters are given, using a symmetric Green's function appr...