April 26/27: I continued with ¡­

April 26/27: I continued with nonlinear semigroup theory, introducing the concepts of nonlinear resolvent and Yosida approximation (of the subdifferential operator), and studying the properties of these operators. Moreover, I started with the proof that the subdifferential of a convex functional generates a semigroup of contractions, which eventually will yield the well-posedness of the corresponding abstract ODE.

Next week I will finish the section on the nonlinear semigroup method.