Proceedings symposium on value distribution theory in several complex variables

178 Pages·1992·5.48 MB·English

by  Wilhelm Stoll

Proceedings Symposium
on Value Distribution Theory in
Several Complex Variables
Notre Dame Mathematical Lectures
Number 12
Proceedings Symposium
on Value Distribution Theory in
Several Complex Variables
on the occasion of the inauguration of Wilhelm Stoll as the
Vincent F. Duncan and Annamarie Micus Duncan
Professor of Mathematics
April 28/29, 1990
University of Notre Dame
Edited by
Wilhelm Stoll
UNIVERSITY OF NOTRE DAME PRESS
NOTRE DAME, INDIANA
Copyright © 1992 by
University of Notre Dame Press
Notre Dame, Indiana 46556
All Rights Reserved
Library of Congress Cataloging-in-Publication Data
Symposium on Value Distribution Theory in Several Complex Variables
(1990 : University of Notre Dame)
Proceedings : Symposium on Value Distribution Theory in Several
Complex Variables : on the occasion of the inauguration of Wilhelm Stoll
as the Vincent F. Duncan and Annamarie Micus Duncan professor of math-
ematics. April 28/29 1990, University of Notre Dame.
p. cm. — (Notre Dame mathematical lectures ; no. 12)
ISBN 0-268-01512-0
1. Value distribution theory—Congresses. 2. Functions of several com-
plex variables—Congresses. I. Stoll, Wilhelm, 1923-
n. Series
QA1.N87 no. 12
[QA331.7]
510 s—dc20 91-42751
[515".94] CIP
Manufactured in the United States of America
CONTENTS
FOREWORD vi
PROGRAM OF THE SYMPOSIUM ix
HIGH POINTS IN THE HISTORY OF VALUE
DISTRIBUTION THEORY OF SEVERAL COMPLEX
VARIABLES
Wilhelm Stol, inaugural lecture: 1
THE NEVANLINNA ERROR TERM FOR COVERINGS,
GENERICALLY SURJECTIVE CASE
Wiliam Chery 37
ON AHLFOR'S THEORY OF COVERING SPACES
David Drasin 54
C"—CAPACITY AND MULTIDIMENSIONAL MOMENT
PROBLEM
Gennadi Henkin and A.A. Shananin 69
NEVANLINNA THEOREMS IN PUSH-FOREWARD
VERSION
Shanyu Ji 86
RECENT WORK ON NEVANLINNA THEORY AND
DIOPHANTINE APPROXIMATION
Paul Vojta 107
DIOPHANTINE APPROXIMATION AND THE THEORY OF
HOLOMORPHIC CURVES
Pit-Mann Wong 115
SOME RECENT RESULTS AND PROBLEMS IN
THE THEORY OF VALUE DISTRIBUTION
Lo Yang 157
FOREWORD
In 1988 Vincent J. Duncan and Annamarie Micus Duncan spon-
sored a chair at the University of Notre Dame in honor of Walter
Duncan, a 1912 graduate of Notre Dame and a long time trustee of
the University. In the fall of that year I was appointed to this chair. In
conjunction with the inaugural lecture, the University of Notre Dame
held a symposium on value distribution in several complex variables
April 28/29, 1990. It was to reflect the growth of this field from its be-
ginning about 60 years ago as well as its connections to related areas.
The Symposium was solely funded by Notre Dame. Thus only speak-
ers present within the USA at the time could be invited and support
was restricted to them. Professor Shiing-shen Chern, who contributed
substantially to the field and helped to build up Mathematics at Notre
Dame, declined to lecture, but he participated actively in the Sympo-
sium as an honored guest. Professor Phillip Griffiths made significant
contributions to the field, but in the end, his obligation as Provost of
Duke University prevented him from coining. The names of the other
invited speakers and the title of their talks can be found in the Sympo-
sium program reprinted below. Two significant lectures preceded the
Symposium the day before. Sponsored by the Physics Department,
Paul Chu gave an University wide address on superconductivity. Pro-
fessor Chern attended his son in law's lecture. Dr. Peter Polyakov, a
close collaborator of Professor Henkin and a recent immigrant to the
USA, spoke about a proof of a 1973 conjecture of mine in a mathemat-
ics colloquium. The Symposium was well attended, but, unfortunately
no precise list of participants was kept.
In these proceedings, some speakers wrote on the topics of their
lectures, some others selected different topics and some did not send
contributions. Serge Lang, who had spoken on William Cherry's re-
sults, requested, that in the Proceedings these results should be com-
municated directly. My inaugural address in the Proceedings is an
expanded version of the original one.
I thank all those who made this Symposium and these Proceed-
ings possible and those who contributed and helped with it. In partic-
ular I thank the donors for their generosity.
Wilhelm Stoll
July 1991
PROGRAM
Saturday, April 28, 1990
9:00-9:15 am Introducing Remarks
Timothy O'Meara, Provost, University of
Notre Dame
Francis Castellino, Dean, College of Science
9:15-10:15 am Inaugural Lecture
Wilhelm Stoll, Notre Dame
Title: High Points in the History of Value
Distribution Theory of Several Complex
Variables
10:30-11:30 am Bernard Shiffman, Johns Hopkins
Title: Bounds On the Distance to Algebraic
n
Varieties in C
12:00 noon Lunch - Morris Inn
2:00-3:00 pm Yum Tong Siu, Harvard
Title: Some Recent Results On
Non-equidimensional Value Distribution
Theory
3:15-4:15 pm David Drasin, Purdue
Title: The Branching Term of Nevanlinna's
Theory
4:30-5:30 pm Paul Vojta, Institute for Advanced Study
Title: Recent Work On Nevanlinna Theory
and Diophantine Approximations
6:30 pm Dinner - Morris Inn
ix
x Program
Sunday, April 29, 1990
9:15-10:15 am Serge Lang, Yale
Title: The Error Term in Nevanlinna Theory
10:30-11:30 am Pit-Mann Wong, Notre Dame
Title: Second Main Theorems of Nevanlinna's
Theory
12:00 noon Lunch - Morris Inn
1:45-2:45 pm Lo Yang, Notre Dame/Academia Sinica, Beijing
Title: Some Results and Problems in the Theory
of Value Distribution
3:00-4:00 pm Gennadi Henkin, Notre Dame/Academy of
Science USSR
Title: The Characterization of the Scattering
Datas for the Schrodinger Operator in
Terms of the d - Equation and Growth
Conditions
HIGH POINTS IN THE HISTORY OF
VALUE DISTRIBUTION THEORY OF
SEVERAL COMPLEX VARIABLES
Wilhelm Stoll
Inaugural Lecture
Timothy O'Meara and Frank Castellino thank your for your kind
introduction. I am deeply moved by your words and by the appoint-
ment to the chair. Foremost I thank the donors Vincent J. Duncan and
Annamarie Micus Duncan for their generosity. My colleagues and I
are most grateful for this recognition of our work by the donors and
the administration of the University.
Ladies and gentlemen, colleagues, speakers and participants!
This inaugural address opens the Symposium on Value Distribution
Theory in Several Complex Variables sponsored by the University
of Notre Dame. Welcome to all of you. An inaugural address, an
Antrittsvorlesung, so late in life seems to be out of place and perhaps
should be called an Abschiedsvorlesung. Yet, hopefully, this is pre-
mature and I can be around a few more years. Taking the hint, I will
look backwards and recall some of the high points in the development
of the theory. Time permits only a few topics.
Looking backwards, out of the mist of time there emerges not an
abstract theory but the lively memory of those who taught me math-
ematics: Siegfried Kerridge, Wilhelm Germann, Wilhelm Schweizer
and later at the University Hellmuth Kneser, Konrad Knopp, Erich
Kamke, G. G. Lorentz and Max Mtiller. Also there appear those who
inspired me but who were not directly my teachers: Heinz Hopf, Her-
mann Weyl, Rolf Nevanlinna and one who is right here with us:
Shiing-shen Chern, we all welcome you. Thirty years ago you re-
cruited me for Notre Dame. You supported the growth of this de-
partment in many ways. Your work on value distribution in several
This research was supported in part by the National Science Foundation Grant
DMS-87-02144.
1
2 High Points in the History of Value Distribution Theory
complex variables counts as one of your many marvelous contributions
to mathematics. Thank you for coming.
The giants of the 19th century created the theory of entire func-
tions. In this century, in 1925, with a stroke of genius, Rolf Nevanlinna
extended this theory to a value distribution theory of meromorphic
functions. His two Main Theorems are the foundation upon which
Nevanlinna theory rests.
In 1933, Henri Cartan [8] proved Nevanlinna's Second Main
Theorem for the case of holomorphic curves. If we view curves be-
longing to the theory of several dependent variables, then Cartan's
paper provides the first theorem in the theory of value distribution in
several complex variables. Thus let me outline his result. However, I
shall use today's terminology and advancement.
For each 0 < r G R define the discs and circle
(1) C[r] = {z G C | \z\ < r} C(r) = {z G C | \z\ < r}
(2) C<r> - {z G C | |*| = r} C* = C - {0}.
An integral valued function v : C —> Z is said to be a divisor if
(3) S = suppz/ = clos{^ G C | i/(z) i=- 0}
is a closed set of isolated points in C. For all r > 0 the counting
function nv of z/ is defined by the finite sum
(4)
For 0 < s < r £ IR, the valence function Nv of v is defined by
(5)
If h ^ 0 is an entire function, let /^(z) be the zero-multiplicity
of h at z. Then /^ : C —- > / is a non-negative divisor called the zero
divisor of h.