An Equivalence Theorem for Series of Orthogonal Polynomials.
نویسنده
چکیده
xj(u, v) = yj(u, v), j = 1, 2, 3, so that again (8) holds. Hence, under our hypotheses, D is mapped isothermically on a spherical surface of finite radius, and circles are not mapped on circles. III. Characterization of Those Isothermic Spherical Maps Which Map Circles on Circles and of Isothermic Maps on Minimal Surfaces.-THEOREM 3. If thefunctions (6) have continuous partial derivatives of the third order in a simply connected domain D, then a necessary and sufficient condition that they map D isothermically either on a spherical surface, carrying circles into circles, or on a minimal surface, is that (8) hold for each circle C in D; further (14), with a = 8, is equivalent to (8). The proof is contained in the proof of Theorem 2.
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ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 25 2 شماره
صفحات -
تاریخ انتشار 1939