Abstract
We extend a result by Rodin, which provides an explicit method for finding the extremal function and the 2-module of a foliated family of curves in R2, to Rn making use of Fuglede’s p-module of systems of measures. The extremal functions are identified and the p-module of systems of measures is computed in condensers of rather general type and in their images under homeomorphisms of certain regularity. At the beginning, we discuss and apply Rodin’s Theorem in order to obtain estimates for the conformal modules of parallelograms and ring domains in terms of directional dilatations.
Similar content being viewed by others
References
R. A. Adams, Sobolev Spaces, Academic Press, New York, San Francisco, London, 1975.
L. Ahlfors, Conformal Invariants: Topics in Geometric Function Theory, McGraw-Hill Book Co., New York, 1973.
L. Ahlfors, Lectures on Quasiconformal Mappings, second edition, American Mathematical Society, Provicence, RI, 2006.
L. Ahlfors and A. Beurling, Conformal invariants and function-theoretic null-sets, Acta Math., 83 (1950), 101–129.
G. D. Anderson, S. L. Qiu, M. K. Vamanamurthy, and M. Vuorinen, Generalized elliptic integrals and modular equations, Pacific J. Math., 192 (2000), 1–37.
H. Aikawa and M. Ohtsuka, Extremal length of vector measures, Ann. Acad. Sci. Fenn. Math., 24 (1999), 61–88.
C. Andreian Cazacu, On the length-area dilatation, Complex. Var. Theory. Appl., 50 (2005), 765–776.
M. Badger, Beurling’s criterion and extremal metrics for Fuglede modulus, Ann. Acad. Sci. Fenn., Math., 38 (2013), 677–689.
M. Brakalova, On the asymptotic behavior of some conformal and quasiconformal mappings, Ph.D. Thesis, Sofia University, Sofia, 1988.
M. A. Brakalova and J. A. Jenkins, On solutions of the Beltrami equation, J. Anal. Math., 76 (1998), 67–92.
M. Brakalova and J. A. Jenkins, On a paper of Carleson: “On mappings conformal at the boundary”, Ann. Acad. Sci. Fenn. Math., 27 (2002), 485–490.
M. Brakalova, Sufficient and necessary conditions for conformality.Part II. Analytic viewpoint, Ann. Acad. Sci. Fenn. Math., 35 (2010), 235–254.
M. Brakalova, On local stability of solutions to the Beltrami equation with degeneration, Complex Anlalysis and Applications,’13, Bulgarian Acad. Sci., Sofia, 2013, pp. 65–76.
M. Csörnyei, S. Hencl, and Y. Malý, Homeomorphisms in the Sobolev space W 1, n-1, J. Reine Angew. Math., 644 (2010), 221–235.
V. Dubinin and M. Vuorinen, On conformal moduli of polygonal quadrilaterals, Israel J. Math, 171 (2009), 111–125.
A. Ya. Dubovickiĭ, On the structure of level sets of differentiable mappings of an n-dimensional cube into a k-dimensional cube, Izv. Akad. Nauk SSSR. Ser. Mat., 21 (1957), 371–408.
H. Federer, Geometric Measure Theory, Springer-Verlag New York Inc., New York, 1969.
B. Fuglede, Extremal length and functional completion, Acta Math., 98 (1957), 171–219.
J. Garnett and D. Marshall, Harmonic Measure, Cambridge University Press, Cambridge, 2005.
F.W. Gehring, Extremal length definitions for the conformal capacity of rings in space, Michigan Math. J., 9 (1962), 137–150.
H. Grötzsch, Eleven papers, Ber. Verh. Sächs. Acad. Wiss., Leipzig, Math. Phys. (1928–1932).
V. Gutlyanskii and O. Martio, Conformality of a quasiconformal mapping at a point, J. Anal. Math., 91 (2003), 179–192.
P. Hajlasz, Change of variables formula under minimal assumptions, Colloq. Math., 64 (1993), 93–101.
P. Hajlasz, Sobolev mappings, co-area formula and related topics, Proceedings on Analysis and Geometry, Izdat. Ross. Akad. Nauk Sib. Otd. Inst. Mat., Novosibirsk, 2000, pp. 227–254.
H. Hakula, A. Rasila, and M. Vuorinen, On moduli of rings and quadrilaterals: algorithms and experiments, SIAM J. Sci. Comput., 33 (2011), 279–302.
J. Hesse, A p-extremal length and p-capacity equality, Ark. Mat. 13 (1975), 131–144.
T. Iwaniec and G. Martin, Geometric Function Theory and Non-linear Analysis, Oxford University Press, New York, 2001.
J. A. Jenkins, Univalent Functions and Conformal mapping, Springer-Verlag, Berlin-Göttingen-Heidelberg, 1958.
O. Lehto, Homeomorphisms with a given dilatation, Proceedings of the 15th Scandanavian Conference, Oslo, 1968, Springer, Berlin, 1970, pp. 58–73.
O. Lehto and K. I. Virtanen, Quasiconformal Mappings in the Plane, Springer-Verlag, New York-Heidelberg, 1973.
J. Malý, D. Swanson, and W. P. Ziemer, The co-area formula for Sobolev mappings, Trans.Amer. Math. Soc., 355 (2003), 477–492.
I. Markina, On coincidence of p-module of a family of curves and p-capacity on the Carnot group, Rev. Mat. Iberoamericana,, 19 (2003), 143–160.
O. Martio and W. P. Zimmer, Luzin’s condition (N) and mappings with nonnegative Jacobians, Michigan Math. J., 39 (1992), 495–508.
F. Morgan, Geometric Measure Theory, a Beginner’s Guide, second edition, Academic Press, Boston, 1995.
M. Ohtsuka, Extremal length and precise functions, Gakkōtosho Co., Tokyo, 2003.
C. Pommeremke, Boundary Behavior of Conformal Maps, Springer Verlag, Berlin, 1992.
A. Rasila and M. Vuorinen, Experiments with moduli of quadrilaterals, Rev. Roumaine Math. Pures Appl. 51 (2006), 747–757.
E. Reich, Steiner symmetrization and the conformal moduli of parallelograms, Analysis and Topology, World Sci. Publ., River Edge, NJ, 1998, pp. 615–620.
E. Reich and H. Walczak, On the behavior of quasiconformal mappings at a point, Trans. Amer. Math. Soc., 117 (1965), 338–351.
B. Rodin, The method of extremal length, Bull. Amer. Math. Soc., 80 (1974), 587–606.
B. Rodin and S. E. Warschawski, Extremal length and the boundary behavior of conformal mappings, Ann. Acad. Sci. Fenn. Ser. A I Math., 2 (1976), 467–500.
B. Rodin and S. E. Warschawski, Extremal length and univalent functions. I. The angular derivative, Math. Z., 153 (1977), 1–17.
V. A. Shlyk, Capacity of a condenser and the modulus of a family of separating surfaces, Zap. Nauchn. Sem. Leningrad. Otdel. Mat. Inst. Steklov. (LOMI), 185 (1990), 168–182, 187; translation in J. Soviet Math. 59 (1992), 1240–1248.
V. A. Shlyk, On the equality between p-capacity and p-modulus, Sibirsk. Mat. Zh., 34 (1993), no. 6, 216–221; translation in Siberian Math. J. 34 (1993), 1196–1200.
O. Teichmüller, Untersuchungen über konforme und quasikonforme Abhildungen, Deutsche Math., 3 (1938), 621–678.
A. Vasil’ev, Moduli of Families of Curves for Conformal and Quasiconformal Mappings, Springer-Verlag, Berlin, 2002.
S. K. Vodopyanov, Regularity of mappings inverse to Sobolev mappings, Mat. Sb., 203 (2012), no. 10, 3–32; translation in Sb. Math. 203 (2012), 1383–1410.
J. Väisälä, On quasiconformal mapping in space, Ann. Acad. Sci. Fenn. Ser. AI 298 (1961).
L. I. Volkovyskii, Investigation of the type problem for a simply connected Riemann surface, Trudy Mat. Inst. Steklov. 34 (1950).
W. P. Ziemer, Extremal length and conformal capacity, Trans. Amer. Math. Soc., 126 (1967), 460–473.
W. P. Ziemer, Extremal length and p-capacity, Michigan Math. J., 16 (1969), 43–51.
W. P. Ziemer, Extremal length as a capacity, Michigan Math. J., 17 (1970), 117–128.
Author information
Authors and Affiliations
Corresponding author
Additional information
The first author was partially supported by a Faculty Research Grant, Fordham University, USA.
The second and third authors were partially supported by the grants of the Norwegian Research Council #239033/F20 and #213440/BG and by EU FP7 IRSES program STREVCOMS, grant no. PIRSES-GA-2013-612669Z
Alexander Vasil’ev passed away on October 19, 2016.
Rights and permissions
About this article
Cite this article
Brakalova, M., Markina, I. & Vasil’ev, A. Extremal functions for modules of systems of measures. JAMA 133, 335–359 (2017). https://doi.org/10.1007/s11854-017-0036-1
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11854-017-0036-1