Residue Definition Pole Definition Meromorphic Function Definition Three-Lines Lemma Analysis Reflexivity of Quotients Analysis Dini's Criterion For Pointwise Convergence Harmonic Analysis Regularity of Inhomogeneous Sobolev Elements for Non-Negative Order Sobolev Spaces Reverse Hölder Inequality Analysis RESET THEOREM Partial Differential Equations Directional Derivatives Vanish at an Interior Extremum Analysis Equivalent Characterisation of Differentiability Multivariable Calculus Analysis Area