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In differential geometry, the Björling problem is the problem of finding a minimal surface passing through a given curve with prescribed normal (or tangent planes). The problem was posed and solved by Swedish mathematician Emanuel Gabriel Björling,〔E.G. Björling, Arch. Grunert , IV (1844) pp. 290〕 with further refinement by Hermann Schwarz.〔H.A. Schwarz, J. reine angew. Math. 80 280-300 1875〕 The problem can be solved by extending the surface from the curve using complex analytic continuation. If is a real analytic curve in ℝ3 defined over an interval ''I'', with and a vector field along ''c'' such that and , then the following surface is minimal: : where , , and is a simply connected domain where the interval is included and the power series expansions of and are convergent.〔Kai-Wing Fung, Minimal Surfaces as Isotropic Curves in C3: Associated minimal surfaces and the Björling's problem. MIT BA Thesis. 2004 http://ocw.mit.edu/courses/mathematics/18-994-seminar-in-geometry-fall-2004/projects/main1.pdf〕 A classic example is Catalan's minimal surface, which passes through a cycloid curve. Applying the method to a semicubical parabola produces the Henneberg surface, and to a circle (with a suitably twisted normal field) a minimal Möbius strip. A unique solution always exists. It can be viewed as a Cauchy problem for minimal surfaces, allowing one to find a surface if a geodesic, asymptote or lines of curvature is known. In particular, if the curve is planar and geodesic, then the plane of the curve will be a symmetry plane of the surface.〔Björling problem. Encyclopedia of Mathematics. URL: http://www.encyclopediaofmath.org/index.php?title=Bj%C3%B6rling_problem&oldid=23196〕 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Björling problem」の詳細全文を読む スポンサード リンク
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