boundaryvalueproblems civilengineering conformalmapping controltheory curves differentialequations dynamicprogramming eigenfunktion engineeringmathematics equations feedbackcontrolsystems finiteelementmethod fluiddynamics geophysics geophysics/geodesy globalanalysis(mathematics) heatequation helmholtzequation invariantimbedding laplacetransformation linearalgebras lineardifferentialequations mathematicalmodels mathematicalphysics mathematics matrices mechanicalengineering methodology numericalanalysis numericalsolutions partial partialdifferentialoperators physicalgeography qa911d872010 relativity(physics) scalarfieldtheory scattering(physics) schwingung spaceandtime surfaces vectorfields vectorspaces welle wellenausbreitung wellengleichung wkbapproximation