Available in electronic format
Available in print format
Proceedings of the American Mathematical Society
Proceedings of the American Mathematical Society
ISSN 1088-6826 (e) ISSN 0002-9939 (p)
     

Farrell sets for harmonic functions

Author(s): Stephen J. Gardiner; Mary Hanley
Journal: Proc. Amer. Math. Soc. 131 (2003), 773-779.
MSC (2000): Primary 31B05; Secondary 41A28
Posted: September 17, 2002
Retrieve article in: PDF DVI PostScript

Abstract | References | Similar articles | Additional information

Abstract: Let $F$ denote a relatively closed subset of the unit ball $B$ of $\mathbb{R} ^{n}$. The purpose of this paper is to characterize those sets $F$ which have the following property: any harmonic function $h$ on $B$ which satisfies $\left\vert h\right\vert \leq M$ on $F$ (where $M>0$) can be locally uniformly approximated on $B$ by a sequence of harmonic polynomials which satisfy the same inequality on $F$. This answers a question posed by Stray, who had earlier solved the corresponding problem for holomorphic functions on the unit disc.


References:

1.
D. H. Armitage and S. J. Gardiner, Classical potential theory, Springer, London, 2001. MR 2001m:31001

2.
A. Bonilla, F. Pérez-González, A. Stray and R. Trujillo-González, Approximation in weighted Hardy spaces, J. Anal. Math. 73 (1997), 65-89. MR 99b:30058

3.
A. A. Danielyan, On some problems that arise from Rubel's problem on joint approximation (Russian), Dokl. Akad. Nauk 341 (1995), 10-12. English translation: Doklady Mathematics 51 (1995), 164-165. MR 96h:30073

4.
S. J. Gardiner, Harmonic approximation, London Math. Soc. Lecture Note Series 221, Cambridge University Press, 1995. MR 96j:31001

5.
S. J. Gardiner, Mergelyan pairs for harmonic functions , Proc. Amer. Math. Soc. 126 (1998), 2699-2703. MR 98k:31004

6.
A. Nicolau and J. Orobitg, Joint approximation in BMO, J. Funct. Anal. 173 (2000), 21-48. MR 2001i:42034

7.
A. G. O'Farrell and F. Pérez-González, Pointwise bounded approximation by polynomials, Math. Proc. Camb. Phil. Soc. 112 (1992), 147-155. MR 93d:30048

8.
F. Pérez-González, $H^{p}$ joint approximation, Proc. Amer. Math. Soc. 102 (1988), 577-580. MR 90a:30109

9.
F. Pérez-González and A. Stray, Farrell and Mergelyan sets for $H^{p}$ spaces $(0<p<1)$, Michigan Math. J. 36 (1989), 379-386.

10.
F. Pérez-González and R. Trujillo-González, Farrell and Mergelyan sets for the space of bounded harmonic functions, in Classical and Modern Potential Theory and Applications, NATO ASI Series C 430, Kluwer, Dordrecht, 1994, pp. 399-412. MR 96e:31006

11.
F. Pérez-González, R. Trujillo-González and A. Stray, Joint approximation in BMOA and VMOA, J. Math. Anal. Appl. 237 (1999), 128-138. MR 2000j:30063

12.
L. A. Rubel and A. Stray, Joint approximation in the unit disc, J. Approx. Theory 37 (1983), 44-50. MR 84m:30064

13.
W. Rudin, Real and complex analysis, Second edition, McGraw-Hill, New York, 1974. MR 49:8783

14.
A. Stray, Characterization of Mergelyan sets, Proc. Amer. Math. Soc. 44 (1974), 347-352. MR 50:13543

15.
A. Stray, Pointwise bounded approximation by functions satisfying a side condition, Pacific J. Math. 51 (1974), 301-305. MR 50:10276

16.
A. Stray, Simultaneous approximation in the Dirichlet space, Math. Scand. 89 (2001), 268-282.
17.
A. Stray, Simultaneous approximation in function spaces, in Approximation, Complex Analysis and Potential Theory, NATO Sci. Series II 37, Kluwer, Dordrecht, 2001, pp. 239-261.

Similar Articles:

Retrieve articles in Proceedings of the American Mathematical Society with MSC (2000): 31B05, 41A28

Retrieve articles in all Journals with MSC (2000): 31B05, 41A28


Additional Information:

Stephen J. Gardiner
Affiliation: Department of Mathematics, University College Dublin, Dublin 4, Ireland
Email: stephen.gardiner@ucd.ie

Mary Hanley
Affiliation: Department of Mathematics, University College Dublin, Dublin 4, Ireland
Email: mary.hanley@ucd.ie

DOI: 10.1090/S0002-9939-02-06776-X
PII: S 0002-9939(02)06776-X
Received by editor(s): April 18, 2001
Received by editor(s) in revised form: October 10, 2001
Posted: September 17, 2002
Additional Notes: This research was partially supported by EU Research Training Network HPRN-CT-2000-00116
Communicated by: Juha M. Heinonen
Copyright of article: Copyright 2002, American Mathematical Society


  AMS Website Logo Small Comments: webmaster@ams.org
© Copyright 2008, American Mathematical Society
Privacy Statement
Search the AMSPowered by Google