This book introduces new methods in the theory of partial differential equations derivable from a Lagrangian. These methods constitute, in part, an extension to

The book is intended as an advanced undergraduate or first-year graduate course for students from various disciplines, including applied mathematics, physics an

Our understanding of the fundamental processes of the natural world is based to a large extent on partial differential equations (PDEs). The second edition of P

The maximum principle induces an order structure for partial differential equations, and has become an important tool in nonlinear analysis. This book is the fi

This text is intended for a beginning graduate course on convexity methods for PDEs. The generality chosen by the author puts this under the classification of "