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Radius of convexity of partial sums of a certain power series

Published online by Cambridge University Press:  09 April 2009

Ram Singh
Affiliation:
Department of MathematicsPunjabi UniversityPatiala, India
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Let , be regular in the unit disc . G. Szegö [5] and Y. Miki [3] proved that if f(z), given by (1), is univalent (starlike with respect to the origin; convex; close-to-convex in E) then any one of the partial sums , is also univalent (starlike with respect to the origin; convex; close-to-convex) in |z| < ¼and that the constant ¼ cannot be replaced by a larger one.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1970

References

[1]Libera, R. J., ‘Some radius of convexity problems’, Duke Math. J., 31 (1964), 143158.CrossRefGoogle Scholar
[2]MacGregor, T. H., ‘Functions whose derivative has a positive real part’, Trans. Amer. Math. Soc. 104 (1962), 532537.CrossRefGoogle Scholar
[3]Miki, Y., ‘A note on close-to-convex functions’, J. Japan, Math. Soc. 8 (1965), 256268.Google Scholar
[4]Noshiro, K., ‘On the theory of schlicht functions’, J. Fac. Sci. Hokkaido Univ. (1) 2 (1934–1935), 129155.Google Scholar
[5]Szegö, G., ‘Zur theorie der schlichten Abbildungen’, Math. Ann. 100 (1928), 188211.CrossRefGoogle Scholar
[6]Warschawski, S., ‘On the higher derivatives at the boundary in conformal mappings’, Trans. Amer. Math. Soc., 38 (1935), 310340.CrossRefGoogle Scholar