Publications Meetings The Profession Membership Programs Math Samplings Policy & Advocacy In the News About the AMS

   
Mobile Device Pairing
Green Open Access
Transactions of the American Mathematical Society
Transactions of the American Mathematical Society
ISSN 1088-6850(online) ISSN 0002-9947(print)

 

Stationary isothermic surfaces and uniformly dense domains


Authors: R. Magnanini, J. Prajapat and S. Sakaguchi
Journal: Trans. Amer. Math. Soc. 358 (2006), 4821-4841
MSC (2000): Primary 35K05, 35K20; Secondary 53A10, 58J70
Published electronically: April 11, 2006
MathSciNet review: 2231874
Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Abstract: We establish a relationship between stationary isothermic surfaces and uniformly dense domains. A stationary isothermic surface is a level surface of temperature which does not evolve with time. A domain $ \Omega$ in the $ N$-dimensional Euclidean space $ \mathbb{R}^N$ is said to be uniformly dense in a surface $ \Gamma\subset\mathbb{R}^N$ of codimension $ 1$ if, for every small $ r>0,$ the volume of the intersection of $ \Omega$ with a ball of radius $ r$ and center $ x$ does not depend on $ x$ for $ x\in\Gamma.$

We prove that the boundary of every uniformly dense domain which is bounded (or whose complement is bounded) must be a sphere. We then examine a uniformly dense domain with unbounded boundary $ \partial\Omega$, and we show that the principal curvatures of $ \partial\Omega$ satisfy certain identities.

The case in which the surface $ \Gamma$ coincides with $ \partial\Omega$ is particularly interesting. In fact, we show that, if the boundary of a uniformly dense domain is connected, then (i) if $ N=2$, it must be either a circle or a straight line and (ii) if $ N=3,$ it must be either a sphere, a spherical cylinder or a minimal surface. We conclude with a discussion on uniformly dense domains whose boundary is a minimal surface.


References [Enhancements On Off] (What's this?)


Similar Articles

Retrieve articles in Transactions of the American Mathematical Society with MSC (2000): 35K05, 35K20, 53A10, 58J70

Retrieve articles in all journals with MSC (2000): 35K05, 35K20, 53A10, 58J70


Additional Information

R. Magnanini
Affiliation: Dipartimento di Matematica U. Dini, Università di Firenze, viale Morgagni 67/A, 50134 Firenze, Italy
Email: magnanin@math.unifi.it

J. Prajapat
Affiliation: Indian Statistical Institute, Stat-Math Unit, 8th Mile, Mysore Road, R.V.C.E. Post, Bangalore 560 059, India
Address at time of publication: Department of Mathematics, Indian Institute of Technology Bombay, Powai, Mumbai 400 097, India
Email: jyotsna@isibang.ac.in

S. Sakaguchi
Affiliation: Department of Mathematics, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama-shi, Ehime 790-8577 Japan
Email: sakaguch@dpc.ehime-u.ac.jp

DOI: http://dx.doi.org/10.1090/S0002-9947-06-04145-6
PII: S 0002-9947(06)04145-6
Keywords: Stationary surfaces, uniformly dense domains, minimal surfaces
Received by editor(s): August 11, 2004
Published electronically: April 11, 2006
Additional Notes: This research was partially supported by a Grant-in-Aid for Scientific Research (B) ($♯$ 12440042) and (B) ($♯$ 15340047) of the Japan Society for the Promotion of Science and by a Grant of the Italian MURST
Article copyright: © Copyright 2006 American Mathematical Society
The copyright for this article reverts to public domain 28 years after publication.