In this book, the functional inequalities are introduced to describe:
(i) the spectrum of the generator: the essential and discrete spectrums, high order eigenvalues, the principle eigenvalue, and the spectral gap;
(ii) the semigroup properties: the uniform intergrability, the compactness, the convergence rate, and the existence of density;
(iii) the reference measure and the intrinsic metric: the concentration, the isoperimetic inequality, and the transportation cost inequality.