Algebra Property of Inhomogeneous Sobolev Spaces Sobolev Spaces Linearity of Directional Derivatives Under Differentiability Analysis Residual Ideality of Semiclassical Symbol Classes Analysis Finite Propagation Speed for Retarded Strictly Hyperbolic Parametrices Analysis BMO and Carleson Measures Analysis Preservation of Holomorphicity under Locally Uniform Convergence Complex Analysis Homeomorphisms Preserve Open and Closed Sets Analysis Universal Property of the Product Topology Topology Analysis Area