| Title: | Nonuniqueness for some linear oblique derivative problems for elliptic equations (English) | 
| Author: | Lieberman, Gary M. | 
| Language: | English | 
| Journal: | Commentationes Mathematicae Universitatis Carolinae | 
| ISSN: | 0010-2628 (print) | 
| ISSN: | 1213-7243 (online) | 
| Volume: | 40 | 
| Issue: | 3 | 
| Year: | 1999 | 
| Pages: | 477-481 | 
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| Category: | math | 
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| Summary: | It is well-known that the ``standard'' oblique derivative problem, $\Delta u = 0$ in $\Omega$, $\partial u/\partial \nu-u=0$ on $\partial\Omega$ ($\nu$ is the unit inner normal) has a unique solution even when the boundary condition is not assumed to hold on the entire boundary. When the boundary condition is modified to satisfy an obliqueness condition, the behavior at a single boundary point can change the uniqueness result. We give two simple examples to demonstrate what can happen. (English) | 
| Keyword: | elliptic equations | 
| Keyword: | uniqueness | 
| Keyword: | a priori estimates | 
| Keyword: | linear problems | 
| Keyword: | boundary value problems | 
| MSC: | 35A05 | 
| MSC: | 35B65 | 
| MSC: | 35J25 | 
| idZBL: | Zbl 1064.35508 | 
| idMR: | MR1732488 | 
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| Date available: | 2009-01-08T18:54:17Z | 
| Last updated: | 2012-04-30 | 
| Stable URL: | http://hdl.handle.net/10338.dmlcz/119103 | 
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| Reference: | [1] Gilbarg D., Trudinger N.S.: Elliptic Partial Differential Equations of Second Order.Springer-Verlag Berlin-Heidelberg-New York (1983). Zbl 0562.35001, MR 0737190 | 
| Reference: | [2] Lieberman G.M.: Local estimates for subsolutions and supersolutions of oblique derivative problems for general second-order elliptic equations.Trans. Amer. Math. Soc. 304 (1987), 343-353. Zbl 0635.35037, MR 0906819 | 
| Reference: | [3] Lieberman G.M.: Oblique derivative problems in Lipschitz domains I. Continuous boundary values.Boll. Un. Mat. Ital. 1-B (1987), 1185-1210. MR 0923448 | 
| Reference: | [4] Lieberman G.M.: Oblique derivative problems in Lipschitz domains II. Discontinuous boundary values.J. Reine Angew. Math. 389 (1988), 1-21. MR 0953664 | 
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