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摘要


Let A denote the class of all functions f analytic in the open unit disc U with f(0) = 0 = f'(0)-1. Let h be any convex univalent analytic function on U with h(0) = 1 and Re h(z) > 0 in U. Let g A be fixed. Denote by S_g (h) the class of all g functions f ε A such that, g*f(z) ≠ 0 in U and a(g*f)'(Z)/(g*f)(z) < h(z), z ε U (< denote subordination). It is proved in this paper that the class S_g(h) is closed under convolution with convex functions. It has also been established that S_g(h) ⊆ S_(Φ*g)(h) where Φ is any convex univalent function in A. Four other classes are also defined and studied using mainly the convex hull method and the methd of differential subordination.

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