Distortion estimates for planar diffeomorphisms
Distortion estimates for planar diffeomorphisms
We define new distortion quantities for diffeomorphisms of theEuclidean plane andstudy their properties. In particular, we obtain composition rulesfor these quantities analogous to standard rules for maps of aninterval. Our results apply to maps with unbounded derivatives andhave important applications in the theory of SRB measures for surfacediffeomorphisms.