A **large diffeomorphism** refers to a diffeomorphism (a smooth, invertible map between differentiable manifolds with a smooth inverse) that can be smoothly deformed or transformed into another diffeomorphism in a way that allows for a significant change in the structure of the manifold. This concept is commonly encountered in the fields of differential geometry and topology.
Articles by others on the same topic
A large diffeomorphism does not approach the identity at the relevant boundary or cannot be continuously deformed to the identity within the allowed gauge transformations. It may therefore act nontrivially on physical states or boundary data.