Abstract
We study the extension problem on the Sierpinski Gasket (SG). In the first part we consider minimizing the functional \(\mathcal {E}_{\lambda }(f) = \mathcal {E}(f,f) + \lambda \int f^{2} d \mu \) with prescribed values at a finite set of points where \(\mathcal {E}\) denotes the energy (the analog of \(\int |\nabla f|^{2}\) in Euclidean space) and μ denotes the standard self-similiar measure on SG. We explicitly construct the minimizer \(f(x) = \sum _{i} c_{i} G_{\lambda }(x_{i}, x)\) for some constants c i , where G λ is the resolvent for λ≥0. We minimize the energy over sets in SG by calculating the explicit quadratic form \(\mathcal {E}(f)\) of the minimizer f. We consider properties of this quadratic form for arbitrary sets and then analyze some specific sets. One such set we consider is the bottom row of a graph approximation of SG. We describe both the quadratic form and a discretized form in terms of Haar functions which corresponds to the continuous result established in a previous paper. In the second part, we study a similar problem this time minimizing \(\int _{SG} |\Delta f(x)|^{2} d \mu (x)\) for general measures. In both cases, by using standard methods we show the existence and uniqueness to the minimization problem. We then study properties of the unique minimizers.
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Research supported by the Mathematics Department of the Chinese University of Hong Kong and the Undergraduate Summer Research Fellowship from the office of Academic Links of the Chinese University of Hong Kong.
Research supported by the National Science Foundation through the Research Experiences for Undergraduates(REU) Program at Cornell, the US NSF grant DMS-1156350.
Research supported by the US NSF grant DMS-1162045.
Research supported by the US NSF grant DMS-1156350.
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Li, PH., Ryder, N., Strichartz, R.S. et al. Extensions and their Minimizations on the Sierpinski Gasket. Potential Anal 41, 1167–1201 (2014). https://doi.org/10.1007/s11118-014-9415-8
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DOI: https://doi.org/10.1007/s11118-014-9415-8
Keywords
- Sierpinski gasket
- Whitney extension theorem
- Extension from finite set of data
- Conductance
- Piecewise harmonic function
- Piecewise biharmonic function
- Haar functions