37cxx37dxx37bxx34cxx34dxx 65l1134b0534d1535b25 boundaryvalueproblems differentialequations diffusion dynamicalsystemsandergodictheory dynamicalsystemswithhyperbolicbehavior dynamics exponentialfunctions linearboundaryvalueproblems mathematicalmodels nonlinear numericalanalysis numericalsolutions ordinarydifferentialequations partialdifferentialequations qualitativepropertiesofsolutions qualitativetheory singularlyperturbedproblems singularperturbations smoothdynamicalsystems:generaltheory topologicaldynamics