The optimal convergence rate of the p-version of the finite element method
SIAM Journal on Numerical Analysis
Stochastic finite elements: a spectral approach
Stochastic finite elements: a spectral approach
A posteriori error estimates for boundary element methods
Mathematics of Computation
Karhunen-Loève approximation of random fields by generalized fast multipole methods
Journal of Computational Physics - Special issue: Uncertainty quantification in simulation science
Sparse second moment analysis for elliptic problems in stochastic domains
Numerische Mathematik
SIAM Journal on Numerical Analysis
Sparse p-version BEM for first kind boundary integral equations with random loading
Applied Numerical Mathematics
A finite element method for elliptic problems with stochastic input data
Applied Numerical Mathematics
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In the present paper we study the approximation of functions with bounded mixed derivatives by sparse tensor product polynomials in positive order tensor product Sobolev spaces. We introduce a new sparse polynomial approximation operator which exhibits optimal convergence properties in L^2 and tensorized H"0^1 simultaneously on a standard k-dimensional cube. In the special case k=2 the suggested approximation operator is also optimal in L^2 and tensorized H^1 (without essential boundary conditions). This allows to construct an optimal sparse p-version FEM with sparse piecewise continuous polynomial splines, reducing the number of unknowns from O(p^2), needed for the full tensor product computation, to O(plogp), required for the suggested sparse technique, preserving the same optimal convergence rate in terms of p. We apply this result to an elliptic differential equation and an elliptic integral equation with random loading and compute the covariances of the solutions with O(plogp) unknowns. Several numerical examples support the theoretical estimates.