This volume presents the proceedings of a series of lectures hosted by the Math ematics Department of The University of Tennessee, Knoxville, March 22-24, 1995, under the title "Nonlinear Partial Differential Equations in Geometry and Physics" . While the relevance of partial differential equations to problems in differen tial geometry has been recognized since the early days of the latter subject, the idea that differential equations of differential-geometric origin can be useful in the formulation of physical theories is a much more recent one. Perhaps the earliest emergence of systems of nonlinear partial differential equations having deep geo metric and physical importance were the Einstein equations of general relativity (1915). Several basic aspects of the initial value problem for the Einstein equa tions, such as existence, regularity and stability of solutions remain prime research areas today. eighty years after Einstein's work. An even more recent development is the realization that structures originally the context of models in theoretical physics may turn out to have introduced in important geometric or topological applications. Perhaps its emergence can be traced back to 1954, with the introduction of a non-abelian version of Maxwell's equations as a model in elementary-particle physics, by the physicists C.N. Yang and R. Mills. The rich geometric structure ofthe Yang-Mills equations was brought to the attention of mathematicians through work of M.F. Atiyah: "J. Hitchin, I."

Renewable energy sources became a key research focus in the field of global environmental governance. Within this context, new technical innovations seek to overcome challenges resulting from volatile renewable energy production and lacking storage capacities. Blockchain, a distributed ledger technology using cryptography, gained prominence as an integral component within the increasingly decentralized and digitalized global energy infrastructure. Against this background, Alexander Freier argues that the application of blockchain technologies represents a viable option to both enhance the efficiency and balancing of renewable energy as well as to subsequently reduce GHG emissions if the following three components are met: the ongoing implementation of technological advancements, an adequate global normative framework, and general trust on behalf of key market actors to promote blockchain in the energy sector on a global scale. Departing from an analysis of the relationship between climate change and energy, Freier conducts a legal analysis to explore possible ʼbottom-upʼ perspectives for the implementation and transfer of technological innovation derived from climate contracts. This analysis examines the technological infrastructure surrounding blockchain energy as well as its application to the Brooklyn MicroGrid in the US and the WindNODE trading platform in Germany from an International Relations perspective.