We answer a question posed in [12] on exponential integrability of functions of restricted $n$-energy. We use geometric methods to obtain a sharp exponential integrability result for boundary traces of monotone Sobolev functions defined on the unit ball.
References
S.-Y. A. Chang and D. E. Marshall, On a sharp inequality concerning the Dirichlet integral, Amer. J. Math., 107(5) (1985), 1015--1033.
Mathematical Reviews (MathSciNet):
MR805803
L. C. Evans and R. F. Gariepy, Measure theory and fine properties of functions, Studies in Advanced Mathematics, CRC Press, Boca Raton, FL, 1992.
B. Fuglede, Extremal length and functional completion, Acta Math., 98 (1957), 171--219.
Mathematical Reviews (MathSciNet):
MR97720
F. W. Gehring, Symmetrization of rings in space, Trans. Amer. Math. Soc., 101 (1961), 499--519.
Mathematical Reviews (MathSciNet):
MR132841
F. W. Gehring, Rings and quasiconformal mappings in space, Trans. Amer. Math. Soc., 103 (1962), 353--393.
Mathematical Reviews (MathSciNet):
MR139735
J. Heinonen, T. Kilpeläinen, and O. Martio, Nonlinear potential theory of degenerate elliptic equations, Oxford Mathematical Monographs, The Clarendon Press Oxford University Press, New York, 1993.
J. Malý, D. Swanson, and W. P. Ziemer, The co-area formula for Sobolev mappings, Trans. Amer. Math. Soc., 355(2) (2003), 477--492 (electronic).
J. J. Manfredi, Weakly monotone functions, J. Geom. Anal., 4(3) (1994), 393--402.
D. E. Marshall, A new proof of a sharp inequality concerning the Dirichlet integral, Ark. Mat., 27(1) (1989), 131--137.
J. Moser, A sharp form of an inequality by N. Trudinger, Indiana Univ. Math. J., 20, (1970/71), 1077--1092.
Mathematical Reviews (MathSciNet):
MR301504
G. D. Mostow, Quasi-conformal mappings in $n$-space and the rigidity of hyperbolic space forms, Inst. Hautes Études Sci. Publ. Math., (34) (1968), 53--104.
Mathematical Reviews (MathSciNet):
MR236383
P. Poggi-Corradini and K. Rajala, An egg-yolk principle and exponential integrability for quasiregular mappings, J. London Math. Soc. (2), 76(2) (2007), 531--544.