This memoir attempts at a systematic study of convergence to stationary state for certain classes of degenerate diffusive equations, taking the general form ${\frac{\partial f}{\partial t}}+ L f =0$. The question is whether and how one can overcome the degeneracy by exploiting commutators.

Table of Contents

• Introduction
• $L=A^*A+B$
• The auxiliary operator method
• Fully nonlinear equations
• Appendices
• Bibliography