A weak-type inequality for differentially subordinate harmonic functions
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Abstract:
Assuming an extra condition, we decrease the constant in the sharp inequality of Burkholder $\mu (|v|\ge 1)\le 2\|u\|_1$ for two harmonic functions $u$ and $v$. That is, we prove the sharp weak-type inequality $\mu (|v|\ge 1)\le K\|u\|_1$ under the assumptions that $|v(\xi )|\le |u(\xi )|$, $|\nabla v|\le |\nabla u|$ and the extra assumption that $\nabla u\cdot \nabla v=0$. Here $\mu$ is the harmonic measure with respect to $\xi$ and the constant $K$ is the one found by Davis to be the best constant in Kolmogorov’s weak-type inequality for conjugate functions.References
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Additional Information
- Changsun Choi
- Affiliation: Department of Mathematics, University of Illinois, 273 Altgeld Hall, 1409 West Green Street, Urbana, Illinois 61801
- Address at time of publication: Department of Mathematics, KAIST Taejon, 305-701 Korea
- Email: cschoi@math.kaist.ac.kr
- Received by editor(s): October 7, 1995
- © Copyright 1998 American Mathematical Society
- Journal: Trans. Amer. Math. Soc. 350 (1998), 2687-2696
- MSC (1991): Primary 31B05, 31B15; Secondary 42A50, 60G42
- DOI: https://doi.org/10.1090/S0002-9947-98-02259-4
- MathSciNet review: 1617340