Wyniki wyszukiwania - BazTech

Ograniczanie wyników

7 Demonstratio Mathematica

Znaleziono wyników: 7

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: funkcje univalentne

Sortuj według:

Ogranicz wyniki do:

Univalence criterion for certain integral operators

Hamada H.

Demonstratio Mathematica

2005

Vol. 38, nr 1

43--46

Pescar investigated the univalence of certain integral operators. We will show that the results are obtained by the Schwarz lemma. We will also give some generalizations.

On the coefficients of a class of univalent functions

Şerb I.

Demonstratio Mathematica

2005

Vol. 38, nr 3

567--578

We consider a class of univalent functions which verify a strong Milin type condition for logarithmic coefficients. This class contains all alfa-Koebe spirallike functions, all extremal points of the class of typically real functions, together with their rotations and multiplicative "compositions". We find some extremal functions of this class.

On a problem H. S. Al-Amiri and M. O. Reade

Singh S., Gupta S.

Demonstratio Mathematica

2005

Vol. 38, nr 2

303--311

In the present paper, the authors investigate the univalence of the functions f, analytic in -E, f(O) = 0, f'(0) = 1 and which satisfy Re [(1 - alfa)f'(z) + alfa (1+ zf''(z): f'(z)] >beta, z is an element of E, where alfa > 0 and 0 < beta < 1. The univalence of such functions has already been established in the case when alfa < 0 and beta = 0 by H. S. Al-Amiri and M. 0. Reade in 1975.

Linear invariance and integral operators of univalence functions

Dorff M., Szynal J.

Demonstratio Mathematica

2005

Vol. 38, nr 1

47--57

In this paper, we study a larger set than (1), namely the set of the minimal invariant family which contains (1), where / belongs to the linear invariant family, and thereby we obtain information about the univalence of (1). In particular, we determine the order of this minimal invariant family in the cases of univalent and convex univalent functions in D. As a result, we find the radius of close-to-convexity and the lower bound for the radius of univalence for the minimal invariant family in the case of convex univalent functions. This allows us to determine the exact region for (a, (3) where the corresponding minimal invariant family is univalent and close-to-convex. These results are sharp and generalize those which were obtained in [11].

Linearly invariant classes of functions analytic in a unit circle of zero type

Kir'ytzkii E. G.

Demonstratio Mathematica

2004

Vol. 37, nr 4

823--845

On certain subclass of analytic functions with complex order

Aouf M. K., Al-amri B. A.

Demonstratio Mathematica

2003

Vol. 36, nr 4

827--838

Integral operator which preserves the univalence in the upper half-plane

Blezu D., Pascu N. N., Pascu R. N.

Demonstratio Mathematica

2003

Vol. 36, nr 1

77--81

In this paper, using the Pfaltzgraff integral operator and the so called "parametric circles method" introduced by N. N.Pascu (1999), we can obtain an univalence criterion for the analytic function denned in the upper half-plane and also for comparison two univalence criteria obtained by a simple composition of functions.