2018/12/31 by Goldstein, Paweł, Hajłasz, Piotr
#26B10 #46E35 (Primary) #74B20 (Secondary) #Classical Analysis and ODEs (math.CA) #FOS: Mathematics #Geometric Topology (math.GT)
paper · doi:10.48550/arxiv.1812.11888
We investigate a known problem whether a Sobolev homeomorphism between domains in ℝn can change sign of the Jacobian. The only case that remains open is when f∈ W1,[n/2], n≥ 4. We prove that if n≥ 4, and a sense-preserving homeomorphism f satisfies f∈ W1,[n/2], f-1∈ W1,n-[n/2]-1 and either f is Hölder continuous on almost all spheres of dimension [n/2], or f-1 is Hölder continuous on almost all spheres of dimensions n-[n/2]-1, then the Jacobian of f is non-negative, Jf≥ 0, almost everywhere. This result is a consequence of a more general result proved in the paper. Here [x] stands for the greatest integer less than or equal to x.