Boundary value problems Mathematical models 24 Theorem proving 14 Boundary conditions 12 Diffraction gratings 12 Problem solving 12 Algorithms 8 Eigenvalues and eigenfunctions 8 Matrix algebra 8 Nonlinear systems 8 Set theory 8 Approximation theory 6 Bessel functions 6 Convergence of numerical methods 6 Dielectric materials 6 Iterative methods 6 Maxwell equations 6 Nonlocal diffusion 6 Coincidence degree 4 Complexity 4 Computational complexity 4 Conditioning 4 Crystals 4 Density (specific gravity) 4 Differential equations 4 Differentiation (calculus) 4 Dirichlet problem 4 Discretized Newton method 4 Electromagnetic wave diffraction 4 Fractional Laplacian 4