ABSTRACT

"Examining a topic that has been the subject of more than 300 articles since it was first conceived nearly 20 years ago, this monograph describes for the first time in one volume the basic theory and multitude of applications in the study of differential subordinations."

chapter 1|5 pages

PRELIMINARIES

1.1. A Short History

chapter |7 pages

r(c) ta-1(t)c-a-1

~ r(a + r(b +

chapter 2|9 pages

THEORY OF SECOND-ORDER DIFFERENTIAL SUBORDINATIONS

2.1. Introduction

chapter |1 pages

+ anzn + ··· be analytic in U with

chapter |1 pages

q'(,

chapter |1 pages

+ anzn + · · ·

If not u au\

chapter |1 pages

dU that p(zo)

lzl < lzlp(z =I = M,

chapter |1 pages

Rea> a then Ll = = {w: >a}, =a= If U

dU \ {1} such that >a I I< I I. =a,

chapter |2 pages

If p .JI[a, and 'lf(p(z), zp'(z), z

chapter |1 pages

= e I

n, = z U and

chapter |1 pages

Rea > 0, satisfies q(U)

J 1}, by using (2.2-7) and (2.2-8) the condition of admissibility z and n

chapter 2|3 pages

4. Examples

chapter |2 pages

+vi; z)] = a+

= Re[pi+a(z)·afpi] =

chapter l|2 pages

'lf(pi,a,JL+vi;z)l;;?: 1, -n[ 1 + p ]/2,

I + Szp'(z)-

chapter |1 pages

fi[O, 1], then I zp"(z) + 4zp'(z) + 2p(z)-I < (M- Ip(z) I <

z in a )] ), ]/2. The second condition in (2.4-7) implies that If p 1 , n]

chapter |1 pages

f(z)

f' + > f(z) >

chapter |2 pages

> 0, let n

= 2enz/(1- = 2e If 0, = b + = + = 0, lim =. This leads to and lim

chapter |1 pages

< 0 and therefore from (2.5-12) we deduce that

2Rec + Imc + nlc I if < 0 we obtain

chapter I|2 pages

I < + 2cfn = en

chapter |8 pages

+ 8), n]. By differentiating (2.5-18) we

= a.+ =

chapter |2 pages

+ p /2. Therefore we conclude that p > 0 .,jj'(z) > 1/2.

= ( ( ) '(

chapter |8 pages

.A, then the following sharp implications hold:

zf'(z)

chapter 3|2 pages

APPLICATIONS OF FIRST-ORDER DIFFERENTIAL SUBORDINATIONS

3.1. First-Order Linear Differential Subordinations

chapter |1 pages

of Theorem 2.3d. We only need to show that

I arg [m·P(z)] I < 2·

chapter |1 pages

Proof. 'V(r,s)

= + sfy, = + ( ml n 1, we conclude that

chapter |1 pages

if y 1, then this theorem reduces to Robinson's differential sub-

z ]II ]a and q(z) 1-z 1-z

chapter |14 pages

If p(z0, then ±1. If we let ri

chapter |11 pages

= = = .A and

= + y] I [ zH'(

chapter |4 pages

If we apply this last theorem to the special relationship between the integral = f]

of Theorem 3.2j, with f] .A = zK'

chapter 3|2 pages

3. Briot-Bouquet Applications in Univalent

_1 I

chapter |3 pages

z)t-

chapter |6 pages

= + = + Bz'

z I is a half-plane. In order to satisfy = > ReP( -1)

chapter |2 pages

If = = =

-1/2 and If of Lis the Libera integral operator defined by

chapter |5 pages

= [f], f *. These functions F and

f satisfy Bz)[l-

chapter |2 pages

fort 0, and lim aI

z and t 0

chapter |8 pages

+ y) -t corresponds to the Briot-Bouquet

If zU, = 0.

chapter |2 pages

+ + 9'[q(z)]

If =

chapter 0|2 pages

Combining all of these cases we have the following result:

if (1/2, lfp p(z) 0,

chapter |2 pages

< a1/3. Therefore, by Theorem 3.4i we deduce the

I 1/4. In this case we have = if I /4, = e(l-c)z] > zp'(z)-

chapter |13 pages

If p is analytic in U, with p(O)

chapter |6 pages

If f S AI 2 -

chapter |6 pages

If = =

f](z) [ (a +

chapter |1 pages

a y > -1 and e :h, with a -

f to be in the set of convex functions and determine

chapter |1 pages

*. The

If = = = if

chapter |2 pages

a, y, o and a be real numbers satisfying

s*,g l[f,g] S*. In addition, if l[f,g] = (g(z)/ O+aRe[zg'(z)_1] o-a.

chapter |1 pages

= if *,

chapter |1 pages

If = = o = = =

chapter |2 pages

fCJ(

If = J(

chapter 74|2 pages

] obtained specific

3.6 Subordination-Preserving Integral Operators

chapter |1 pages

+ p(z) + -

chapter |6 pages

> 0. We show that Re \jl(pi, a) 0 by using (3.6-12) and

I 1+ I y 1+ 2 Im · Im y y I 2Re y, I + I P - y I )

chapter 4|1 pages

APPLICATIONS OF SECOND-ORDER DIFFERENTIAL SUBORDINATIONS

4.1. Second-Order Linear Differential Subordinations

chapter |2 pages

= + z)/(1-

chapter |4 pages

+ B(z)zp'(z) + C(z)p(z) + D(z) Mz

chapter I|3 pages

+ C(z)p(z) + D(z) I < M,

"' '¥ -1) + + -IR(z)l -l)(m-

chapter |1 pages

> 0, which will then lead to the desired

If W, Z C and -1 = -1)] I < rt/2. Using

chapter |1 pages

(U) at

chapter |1 pages

= At + +

z/(B + A simple calculation shows that

chapter |3 pages

> 0, which implies that S

if Tis = I < 1/4, If =

chapter |2 pages

e with s; 1 satisfies (4 .2-3), we obtain:

f [ 1, n ], then

chapter |2 pages

If = =

chapter |1 pages

P= =

chapter |9 pages

f(J),

chapter |1 pages

if y2:1/2 and r

chapter |1 pages

= = -

A. If

chapter |8 pages

p + y + + +

chapter |1 pages

If c 1 + N(a -

-l;z). If If If > >

chapter |2 pages

r(c)r(d -

chapter |1 pages

If cR(a), where R(a) is given by (4.5-10), then

Jt-l/2(1- 5/4. In the special case c = 3/2, iz

chapter |4 pages

< b < c and a [-2, 0). By employing (1.2-14) and

z U. Using this result in the above equation we obtain F'(a,b,c;z) 0 for z U.

chapter 4|5 pages

6. The Schwarzian and Starlikeness

chapter 5|7 pages

SPECIAL DIFFERENTIAL SUBORDINATIONS

5.1. Conditions for Special Subclasses of Starlike Functions

chapter |3 pages

If = FE >

+ naf2, if < If a

chapter |4 pages

If = ( + az ), then

chapter |3 pages

If =

in that * [ ]

chapter |2 pages

> 0, 0 <

S*[p].

chapter |3 pages

If f

a zp'(z) ( + z

chapter 14|1 pages

] and in 1991 [ 228] the result M

chapter |2 pages

f"(z)// '(z) I M

1/"(z)//'(z )l If I M2.832 .. · ,

chapter |6 pages

If A2

4ln2+1t-2 -2 _z_ > f S *.

chapter 5|4 pages

3. On a Theorem of Robertson

zj"(z)/f'(z) and zj'(z)/f(z) play a fundamental role in the z/'(z) 2 S*(a), If = f(z)/[zf'(z)], fi[l,l]

chapter |4 pages

a(k).

)ln[l-l/k] = if < [I+ f S*( If .A, j(z)· +II < I zj'(z) 0, when a -

chapter 5|3 pages

5. Functions with Bounded Turning And Starlike Functions

I arg f'(z) I rt/2, and arg f'(z) is the angle of turn (or rotation) of the z under the mapping f . It is well known that f S *. This section describes some of

chapter |1 pages

+ z ]

I + arg (p(z) zp'(z)) I I arg p(z) I I arg I f .S *.

chapter |1 pages

f e .Aand

= < -

chapter |1 pages

Wim If

I I < IP(z)- I I < N

chapter |5 pages

= = If

chapter |6 pages

1 <

FE S*. If y) if

chapter |4 pages

> 0,

= = and = F(z) f'(z) = f(z).

chapter |1 pages

f; z)

chapter 6|13 pages

HIGHER ORDER DIFFERENTIAL SUBORDINATIONS

6.1. Introduction

chapter |4 pages

)e-i

-1),

chapter |2 pages

f is analytic and has a zero of order k, then

= + + f J./ and 1

chapter |1 pages

If B

~ zr-k > 0.

chapter 7|3 pages

DIFFERENTIAL SUBORDINATIONS OF SEVERAL COMPLEX VARIABLES

7.1. Preliminary Lemmas

chapter |3 pages

F: e and let 0 be a complete

)/dz] 0, and I F(wz I 1, for w e U. Since F(O) = [I lim(l-r)-

chapter |1 pages

S au

f( P.n) q(V), then there exist points , au f(zo)

chapter |1 pages

= If z

II}, ),/(zo)), I : I ' I I 'o I } I 'o ) I .

chapter |3 pages

en with the supremum norm

f(zo) = {II f(z) : },

chapter |1 pages

< r< 1, zJBr. and let

= {II /(z) II: II}, /IIJ(z = mj(z

chapter |5 pages

A e and > 0 is chosen sufficiently small so that

zpoint of maximum the = mf(zo), = 1/ Df(z A 0.

chapter |6 pages

f is locally biholomorphic at z

dEn W at the point dEn at z

chapter I|3 pages

' I z

u '0 {I g(') I:

chapter |1 pages

< M, and let 'I'[M]. If the differential equation

llf(z) + f(z)(z f(z) M.

chapter 7|1 pages

.3. Dominants and Admissible Functions in

f and g be f is said to be subordinate tog, written f g or /(z) g(z), if there exists a mapping ..J./(B), with = f(B) f g if and only if f(O) [50]

chapter |1 pages

fi(B) and biholomorphic

chapter c|4 pages

en and let g be a biholomorphic

chapter |2 pages

= { (u, en en: II= and vII }·

[Dg(')r II' = Iff =

chapter |3 pages

f Then there is ae2, · · · , n} such that

C·zf' h(z),

chapter 8|1 pages

APPLICATIONS

SUBORDINATIONS 8.1. Harmonic Functions

chapter |6 pages

+ 2(Im P(z ))p + 1 -

f e 1:and f'(z) +

chapter |1 pages

THEOREM 8.2j. [ 247 ] Let a < 1, 0 < y, f and

= + y) = }:.r f then

chapter |4 pages

+ n + 1 > 0 and g .J./[0, n].

chapter 9|1 pages

] [ 254] e then

llogj'(z)l ln[ ]. f(z) = { f f >

chapter |1 pages

f(z) z, then f e

if and if /'(z) > 0.

chapter |2 pages

If =

= {z >a}. z e -1a, then by the normalization (8.3-1) we have z + a, where e = 0,

chapter |5 pages

f JJ

f, g e JJ

chapter |5 pages

'I': CxU ~ C that

+kim + Cim + Im 0, = = 0,

chapter |3 pages

If a1/2, 0 and

= 0, a(llf(z)ll + llzf'(z)ll) + Plzl < f(z)ll < I. = 1/2 =

chapter |4 pages

APPENDIX CONVEXITY OF BERNOULLI FUNCTIONS

= z/(ez - lzl < 2n, and in such a 2 + z '

chapter |2 pages

f is convex, but that f is convex f is not known.

f in I (e-z+z-1)z

chapter |16 pages

BIBLIOGRAPHY

chapter |10 pages

a, L'A nalyse Numerique et la Theorie de

chapter |2 pages

LIST OF SYMBOLS

=..A, A[f]

chapter L|1 pages

[f]

Ly[f] L(z,t)

chapter 452|3 pages

S[il]

S*[p] s*n.An = S*(a)n.An s*[il] U=U\{o}