NA Digest Monday, August 7, 1995 Volume 95 : Issue 31

Today's Editor:
Cleve Moler
The MathWorks, Inc.

Submissions for NA Digest:

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Information about NA-NET:

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URL for the World Wide Web: -------------------------------------------------------

From: Nick Higham <>
Date: Thu, 3 Aug 95 14:25:53 BST
Subject: Report and Photos from LAA95, Univ. Manchester

The IMA Conference on Linear Algebra and Its Applications
was held at the University of Manchester, July 10-12 1995.

A report on the conference, written by Alison Ramage of Strathclyde
University, together with 20 photos from the conference (scanned at a
modest 100 dpi), is available from the Web page

Among the photos are ones of the winning posters from the poster competition.

---Nick Higham


From: Daniel Zwick <>
Date: Mon, 31 Jul 1995 11:45:08 +0200 (MET DST)
Subject: Fitting Lines and Planes

Dear colleagues,
I am preparing a survey talk on algorithms for fitting lines to data
in R^2 and R^3 and planes to data in R^3. For example, I plan to include
a discussion of both orthogonal and ordinary L_2, L_\infty, L_1, and LMS
fitting. If you could send me a short e-note directing me to any references
on this subject, especially those not already included in the book
"Mathematical Algorithms for Linear Regression," Spaeth, 1987, I would be
very grateful.
Dan Zwick

Daniel S. Zwick University of Bonn, SFB 350
Von-Claer-Strasse 60 Telephone (+49) 2241 205444
53757 Sankt Augustin E-mail:


From: Carsten Nordstroem Jensen" <>
Date: Wed, 2 Aug 1995 13:02:08 +0200 (METDST)
Subject: Seeking Path Finding Software

I am a Ph.D. student at The Technical University of Denmark, working on
various non-linear railway dynamical problems. In this context I am looking
for a public domain program for numerical bifurcation analysis and path
finding, preferably in FORTRAN. I have been working with the program
PATH but find it's not sufficiently robust for large systems. The computing
environment is a HP9000 (Model 700) with HP-UX (Unix).

Carsten Nordstroem Jensen


From: Hans Mittelmann <>
Date: Fri, 4 Aug 1995 14:14:49 -0700
Subject: Decision Tree for Optimization Software


A decision tree and guide to mostly public domain optimization
software (for NLP and LP) is available in ASCII (guide.txt) and
PostScript ( through anonymous ftp to

This is an admittedly subjective list meant not for experts but
for someone in need of a quick pointer to suitable software for a
specific problem. An HTML version is in preparation.


From: Dianne O'Leary <>
Date: Fri, 4 Aug 1995 14:24:18 -0400
Subject: Householder Meeting Announcement

The Householder Meeting on Numerical Algebra will be held
Monday June 17 - Friday June 21, 1996 in Pontresina, Switzerland,
at the Kronenhof. More complete information about the meeting and
the Householder Prize can be found at the Website

and these files are also available via ftp from in directory pub/faculty/oleary.

This meeting is the thirteenth in a series, previously called
the Gatlinburg Symposia. The name honors Alston S. Householder,
one of the pioneers in numerical linear algebra and organizer
of the first four meetings. The meeting has traditionally been
held in an isolated location and is very informal in style.
Each attendee is given the opportunity to present a talk, but
a talk is not mandatory. The format of the meeting includes
scheduled presentations during the day and more informal
evening sessions that are organized on-site. Spirited
discussion is encouraged.

At the meeting, the Householder VII prize will be awarded for
the best thesis in numerical algebra written since 1 January 1993.

We hope that the meeting will be attended by recent entrants
into numerical algebra as well as more experienced researchers.
We encourage attendance by core numerical linear algebra
researchers, matrix theoreticians, and people in applications
such as optimization, signal processing, control, etc.

The Program Committee welcomes your contribution. The meeting
facility in Pontresina holds only 125 people, however, so attendance
may need to be limited. We are seeking funding to provide financial
assistance to recent Ph.Ds and others who might need it.

For full consideration, the committee must receive your abstract
by 5 January 1996. Please use the format described in the "abstract"
file on the Website and ftpsite. The committee expects to complete the
list of attendees and scheduled presentations by 15 February 1996.

After reading the files in the Website or ftpsite, if you have any
questions about local arrangements, please contact Martin Gutknecht: Other questions can be directed to

The Program Committee:
A. Bjorck
A. Bunse-Gerstner
T. Chan
C. Davis
A. George
N. Higham
D. O'Leary (chair)
B. Parlett
G. W. Stewart
P. Van Dooren
C. Van Loan
M. Gutknecht (ex officio)
W. Gander (ex officio)


From: Don Estep <>
Date: Mon, 31 Jul 1995 18:37:27 -0400
Subject: Conference on Dynamical Numerical Analysis

Second Announcement
July 25, 1995
Conference on Dynamical Numerical Analysis
Georgia Tech, Atlanta. December 14-16, 1995

This is a three day conference on dynamical numerical
analysis. Specific topics represented include: convergence
of integration algorithms over long time intervals including
long time error bounds and convergence of invariant sets;
stability of integration algorithms over long time intervals
including preservation of dynamical structure; new approaches
to error analysis, including shadowing results and backward
error analysis; design of computational techniques for invariant
sets including algorithms to compute invariant torii, inertial
manifolds, heteroclinic orbits, homoclinic orbits, and so forth.

The following people are giving invited talks:

D. Aronson U. Ascher W. Beyn E. Doedel
C. Foias E. Hairer A. Iserles P. Kloeden
S. Larsson J. Lorenz K. Palmer G. Raugel
R. Russell J. Sanz-Serna R. Skeel D. Stoffer
A. Stuart E. Titi J. Yorke.

There will also be concurrent sessions of twenty minute
contributed talks.

A refereed volume of the Annals of Numerical Mathematics will
be devoted to works presented at this conference.

Interested parties who have not already contacted us are
encouraged to do this so that they can be added to our mailing

Part of the funds available for the conference are earmarked
for graduate student participation. Students interested in
attending the conference are encouraged to contact us directly.

We prefer correspondence by e-mail.

Sincerely, Luca Dieci and Don Estep.
School of Mathematics, Georgia Institute of Technology
Atlanta, GA, 30332 U.S.A.


From: Jan Verwer <>
Date: Tue, 1 Aug 1995 18:34:32 GMT
Subject: Workshop on Innovative Time Integrators


This workshop takes place at CWI (Center for Mathematics and Computer Science)
in AMSTERDAM, The Netherlands. The focus is on nonstandard ODE and PDE
time-stepping techniques, Keywords for lectures are classified into two main


The workshop is organized by CHUS SANZ-SERNA, Universidad de Valladolid, Spain
and JAN VERWER from CWI, with financial support provided by the EC/HCM program
'The Equations of Fluid Mechanics and Related Subjects'. This support covers
local expenses of participants. Part of the participants will belong to research
groups from the HCM network and part from outside the network. The number of
attendees is limited to approximately 35 of which about 3/4 will be from
outside. The workshop is open to anyone interested, but, since there is
limited space, participation is by invitation only. Rules for participation
can be found in the FULL ANNOUNCEMENT which can be obtained from Mrs. Simone
Panka-van der Wolff (, subject HCM Workshop). Deadline for
application, through submitting a 3-page Latex abstract, is Nov. 1, 1995.
This abstract has to be mailed both to and
(subject HCM Workshop).


From: Jerzy Wasniewski <>
Date: Fri, 4 Aug 1995 13:01:37 +0200 (METDST)
Subject: PARA95, Last Call for Registration




The registration and hotel reservation forms should arrive no
later than August 10, 1995
The PARA95 workshop information are available by anonymous ftp:

ftp (or
<your email address>
cd uni-c/unijw/para95

Registration fees are:
University: DKK 1100 tutorial and 2300 workshop
Industry: DKK 1700 tutorial and 3000 workshop

Jerzy Wasniewski
Tel: + (45)45 883 999 after the tone 2426
Fax: + (45)45 930 220


From: Richard Bartels <>
Date: Sat, 5 Aug 95 11:37:26 -0400
Subject: Call for Papers, Graphics Interface '96

Graphics Interface '96 is interested in papers on such numerically-oriented
topics as scientific visualization, dynamic simulation, geometric modeling,
image processing, radiance/radiosity algorithms, wavelet applications.

Information may be found at

Deadline for papers is 31 October.

Richard Bartels


From: John Burns <>
Date: Tue, 1 Aug 1995 15:16:48 -0400
Subject: Postdoctoral Position at Virginia Tech


The Interdisciplinary Center for Applied Mathematics at
Virginia Tech, in collaboration with the Tektronix, Inc. in
Wilsonville, Oregon, expects to make a university/industry
cooperative postdoctoral appointment, to start August 16,
1995. However, we will continue to accept applications until
the position has been filled. The initial appointment will
be in the area of applied and computational mathematics and
is funded for one year with the possibility of continuing the
position for a second year.

The successful candidate for this position will be expected
to participate in a collaborative multidisciplinary team
carrying out fundamental research in optimal design and
control of fluid flow systems. The goal of the joint
project is to develop and improve analytical and
computational tools for designing ink-jet printers. The
physical phenomena are largely fluid mechanics, including
surface tension and free-surface effects in drop formation.
The design and control issues range from shape optimization
problems to nonlinear feedback control of Navier-Stokes
equations. Since the research efforts will require physical
modeling of fluid flows, optimization based design, control
of partial differential equations and computational skills,
candidates who are outstanding in at least one of these
areas and willing and able to learn quickly in the others
will be given highest priority. This position offers a
unique opportunity for interdisciplinary postdoctoral
research on a mathematical project arising in an
industry/university collaborative effort. The postdoctoral
fellow will be expected to split time between Virginia Tech
and Tektronix and hence must be willing to travel between
the two sites.

Applicants should send a curriculum vitae, brief description
of research interests and three letters of recommendation

Professor John A. Burns, Director
Center for Optimal Design and Control
Wright House - West Campus Drive
Virginia Tech
Blacksburg, VA 24061-0531

Virginia Tech has a strong commitment to the principle of
diversity and, in that spirit, seeks a broad spectrum of
candidates including women, minorities, and people with


From: Ian Sloan <sloan@solution.maths.unsw.EDU.AU>
Date: Thu, 3 Aug 1995 16:40:19 +1000
Subject: Postdoctoral Position at University of New South Wales


A few months ago I placed a preliminary notice of the following position in
the na-digest. If you are one of those who responded, please contact
me again, because I managed (sorry!) to lose some electronic files while
travelling around Europe.

The University of New South Wales is located in Sydney, about
8 kilometres from the city centre and 3 kilometres from the Pacific
Ocean beaches.

It is envisaged that the person appointed will be physically located
in the School of Mathematics, and will interact strongly with the numerical
analysis group at the University of New South Wales.

Other things being equal, we will be particularly happy to appoint
someone who is able to take up the appointment in the next few months.

Please note the early closing date.

Ian Sloan (e-mail:


Applications are invited for a Research Associate Position on the project
'Computable Error Bounds for the Finite Element Method', funded by the
Australian Research Council, and held by Professor I.H. Sloan and
Associate Professor D.W. Kelly.

The project extends procedures already developed for obtaining useful
and reliable pointwise error bounds in the finite element method; the
extensions are particularly focussed on non-linear problems. The
successful applicant will have a PhD in a relevant discipline, strong
research experience involving scientific computation, and a good
knowledge of mathematical analysis.

A knowledge of the following areas would be desirable: partial differential
equations, the finite element method, the boundary element method,
numerical analysis, and non-linear analysis. He or she will have access
to Unix workstations, and opportunities to use, and receive training on,
other advanced computing equipment, including a 32-processor
Thinking Machines CM5 parallel computer and other equipment now in prospect.
A knowledge of Equal Employment Opportunity and Affirmative Action Principles
is required for all employees of UNSW. Appointment on either a full-time
or fractional basis will be considered.

Appointment will be initially for one year with the possibility of renewal for
a further year.

Salary range: $Australian 37,345 - $Australian 40, 087

Further information can be obtained from Professor I.H. Sloan on e-mail or Fax +61-2-385 1071, or Associate Professor D.W.
Kelly on e-mail and Fax +61-2-663 1222.

Applications close: 20 August 95

Applicants should submit an application that specifically addresses the
selection criteria, quoting reference number 461. Include business and
private telephone numbers, e-mail addresses, a complete resume including
copies of academic transcript and qualifications, a list of
publications, and the names, addresses, and fax numbers and/or
e-mail addresses of at least two referees to: The Recruitment
Officer, Human Resources, UNSW, Sydney 2052, Australia; or if time is short,
by e-mail to, with the request that the application be


From: Marcia Saito <saito@BEST.CIMS.NYU.EDU>
Date: Thu, 3 Aug 1995 17:43:44 -0400 (EDT)
Subject: Position at New York University

Courant Institute of Mathematical Sciences

New York University/The Courant Institute anticipate at least one
interdisciplinary faculty position in the Biosciences, to begin as early
as September 1996. The appointment will be at the senior level.
Applicants should have truly outstanding research accomplishments in one of
the Biosciences with interdisciplinary, computational, and mathematical
interests. Applications should be addressed to: Mrs. Frances Adamo,
Courant Institute of Mathematical Sciences, 251 Mercer Street, New York,
NY 10012. New York University is an affirmative action/equal
opportunity employer.


From: Journal of Molecular Modeling <>
Date: Sat, 5 Aug 95 14:58:53 METDST
Subject: New Electronic Journal on Molecular Modeling


The Computer-Chemie-Centrum in collaboration with Springer presents the
Journal of Molecular Modeling, the first fully electronic journal in chemistry.
The Journal of Molecular Modeling is a fully citeable (CAS, ISSN), peer reviewed
journal making use of the advantages of modern communication technologies.
Full papers can be published on a timescale of short communications in
conventional journals, opening an unprecedentedly fast way of presenting a
comprehensive view of leading edge research.
The electronic way of publishing allows the use of sophisticated
full colour presentation material (graphics, 3D-structures, animations etc.),
providing also for a continuous information service to authors and
subscribers through our WWW-homepage
(URL: hhtp://

Authors are encouraged to submit papers to the Journal of Molecular Modeling
and make use of the advanced way of publishing in chemistry.


From: SIAM <>
Date: Thu, 03 Aug 95 14:05:02 EST
Subject: Contents, SIAM Applied Mathematics

SIAM JOURNAL on Applied Mathematics
OCTOBER 1995 Volume 55, Number 5

The Dynamics of Spray-Formed Billets
Ian A. Frigaard

Simulations of Unsteady Compressible Fluid Motion by an Interactive Cored
Particle Method
Yoshifumi Ogami and Angela Y. Cheer

The Oseen Drag at Infinite Reynolds Number
A. J. Weisenborn and B. I. M. ten Bosch

Superheating Field of Type II Superconductors
S. Jonathan Chapman

A Mean-field Model of Superconducting Vortices in Three Dimensions
S. Jonathan Chapman

Motion of Vortices in Type II Superconductors
S. Jonathan Chapman and G. Richardson

Spatial Structure of the Focusing Singularity of the Nonlinear Schrodinger
Equation: A Geometrical Analysis
Nancy Kopell and Michael Landman

A Finite Element/Spectral Method for Approximating the Time-Harmonic Maxwell
System in R^3
Andreas Kirsch and Peter Monk

Elastic Herglotz Functions
George Dassios and Zafiria Rigou

Tip Reconstruction for the Atomic Force Microscope
Richard Miller, James Vesenka, and Eric Henderson

Understanding Propagation Failure as a Slow Capture Near a Limit Point
Victoria Booth and Thomas Erneux

A Dynamic Numerical Method for Models of the Urine Concentrating Mechanism
H. E. Layton, E. Bruce Pitman, and Mark A. Knepper

Transport Equations and Indices for Random and Biased Cell Migration Based on
Single Cell Properties
Richard B. Dickinson and Robert T. Tranquillo

Transonic Flow Around Optimum Critical Airfoils
Zvi Rusak


From: Richard Brualdi <>
Date: Fri, 4 Aug 1995 09:06:20 -0500 (CDT)
Subject: Contents, Linear Algebra and its Applications

Contents Volumes 226-228, Sept-Oct 1995

Special Issue Honoring J. J. Seidel

Preface 1

Rene Peeters (Tilburg, the Netherlands)
Uniqueness of Strongly Regular Graphs Having Minimal p-Rank 9

L. Storme and J. A. Thas (Ghent, Belgium)
k-Arcs and Partial Flocks 33

Aart Blokhuis, Henny A. Wilbrink (Eindhoven, the Netherlands),
and Attila Sali (Budapest, Hungary)
Perfect Sumsets in Finite Abelian Groups 47

M. Bernstein and N. J. A. Sloane (Murray Hill, New Jersey)
Some Canonical Sequences of Integers 57

R. B. Bapat (New Delhi, India)
Permanents, Max Algebra and Optimal Assignment 73

Dina Ghinelli (Rome, Italy) and Stefan Lowe (Braunschweig, Germany)
Generalized Quadrangles With a Regular Point and Association Schemes 87

A. J. Hoffman, P. Wolfe (Yorktown Heights, New York),
and M. Hofmeister (Munich, Germany)
A Note on Almost Regular Matrices 105

Peter J. Cameron (London, England)
Sequence Operators From Groups 109

S. E. Payne (Denver, Colorado)
A Tensor Product Action on q-Clan Generalized
Quadrangles With q=2e 115

Edwin R. van Dam (Tilburg, the Netherlands)
Regular Graphs With Four Eigenvalues 139

Bruce Reznick (Urbana, Illinois)
Some Constructions of Spherical 5-Designs 163

D. G. Higman (Ann Arbor, Michigan)
Rank 5 Association Schemes and Triality 197

Yury J. Ionin and Mohan S. Shrikhande (Mt. Pleasant, Michigan)
Equidistant Families of Sets 223

Christopher Parker (Birmingham, England) and
Vladimir D. Tonchev (Houghton, Michigan)
Linear Codes and Doubly Transitive Symmetric Designs 237

Peter Rowlinson (Stirling, Scotland)
Star Partitions and Regularity in Graphs 247

A. E. Brouwer (Eindhoven, the Netherlands)
Toughness and Spectrum of a Graph 267

C. D. Godsil and J. H. Koolen (Waterloo, Ontario, Canada)
On the Multiplicity of Eigenvalues of Distance-Regular Graphs 273

Peter Boyvalenkov (Sofia, Bulgaria)
Computing Distance Distributions of Spherical Designs 277

Arjeh M. Cohen (Eindhoven, the Netherlands) and
David B. Wales (Pasadena, California)
SL(3, 3) is Not a Maximal Subgroup of the Lie Group of Type F4 287

Hans Sterk (Eindhoven, the Netherlands)
Lattices and K3 Surfaces of Degree 6 297

Hans Cuypers (Eindhoven, the Netherlands)
Regular Quaternionic Polytopes 311

W. Plesken (Aachen, Germany)
Solving XXtr=A Over the Integers 331

F. van der Blij (Bilthoven, the Netherlands)
Regular Polygons in Euclidean Space 345

M. L. J. Hautus (Eindhoven, the Netherlands)
Substitution of Matrices Over Rings 353

Irving Kaplansky (Berkeley, California)
A Contribution to von Neumann's Theory of Games. II 371

H. S. M. Coxeter (Toronto, Ontario, Canada)
Some Applications of Trilinear Coordinates 375

Ross Baldick (Austin, Texas)
Refined Proximity and Sensitivity Results in Linearly
Constrained Convex Separable Integer Programming 389

Richard A. Brualdi (Madison, Wisconsin) and
Suk-Geun Hwang (Taegu, Republic of Korea)
Matrices All of Whose Principal Submatrices of Some
Order Have a Nonzero Permanent 409

J. Angel, C. Trimble (Las Vegas, Nevada), B. Shook
(San Diego, California), and A. Terras (La Jolla, California)
Graph Spectra for Finite Upper Half Planes Over Rings 423

Edward Spence (Glasgow, Scotland)
Regular Two-Graphs on 36 Vertices 459

S. A. Hobart (Laramie, Wyoming)
Krein Conditions for Coherent Configurations 499

Hein van der Holst (Amsterdam, the Netherlands),
Laszlo Lovasz (New Haven, Connecticut), and
Alexander Schrijver (Amsterdam, the Netherlands)
On the Invariance of Colin de Verdiere's Graph
Parameter Under Clique Sums 509

Maurits de Graaf and Alexander Schrijver
(Amsterdam, the Netherlands)
Characterizing Homotopy of Systems of Curves on a Compact
Surface by Crossing Numbers 519

G. Eric Moorhouse (Laramie, Wyoming)
Two-Graphs and Skew Two-Graphs in Finite Geometries 529

Laszlo Lovasz (New Haven, Connecticut) and
Akos Seress (Columbus, Ohio)
The Cocycle Lattice of Binary Matroids, II 553

I. Barany (Budapest, Hungary), H. Bunting,
D. G. Larman (London, England), and J. Pach
(New York, New York)
Rich Cells in an Arrangement of Hyperplanes 567

Renee Woo (Auckland, New Zealand) and Arnold Neumaier
(Wien, Austria)
On Graphs Whose Smallest Eigenvalue is at Least _1_2 577

Willem H. Haemers (Tilburg, the Netherlands)
Interlacing Eigenvalues and Graphs 593

R. H. Jeurissen (Nijmegen, the Netherlands)
Special Sets of Lines in PG(3, 2) 617

Rajendra Bhatia (New Delia, India)
Perturbation Bounds for the Operator Absolute Value 639

A. R. Calderbank (Murray Hill, New Jersey) and
Gary McGuire (Pasadena, California)
Z4-Linear Codes Obtained as Projections of Kerdock and
Delsarte-Goethals Codes 647

Michel Deza (Paris, France) and Viatcheslav Grishukhin
(Moscow, Russia)
Delaunay Polytopes of Cut Lattices 667

Pierre de la Harpe (Geneve, Switzerland) and
Francois Jaeger (Grenoble, France)
Chromatic Invariants for Finite Graphs: Theme and
Polynomial Variations 687

J. van den Heuvel (Burnaby, British Columbia, Canada)
Hamilton Cycles and Eigenvalues of Graphs 723

G. B. Khosrovshahi and CH. Maysoori (Tehran, Iran)
On the Bases for Trades 731

William M. Kantor (Eugene, Oregon)
Quaternionic Line-Sets and Quaternionic Kerdock Codes 749

Author Index 781


End of NA Digest