An extended interview with Professor Henryk Woźniakowski, a specialist in computational mathematics, co-author and author of many fundamental information-based complexity (IBC) theorems and researcher in tractability of multivariate problems. Professor Woźniakowski answers the questions concerning mathematics and life with particular emphasis on the period of Solidarity and the political changes of the 80s and early 90s of the last century, in which he took an active part.
Wywiad-rzeka z profesorem Henrykiem Woźniakowskim, specjalistą w zakresie matematyki obliczeniowej, współtwórcą i autorem wielu podstawowych twierdzeń teorii analitycznej złożoności obliczeniowej (information-based complexity, IBC) oraz badaczem podatności zadań obliczeniowych zależnych od bardzo wielu zmiennych. Profesor odpowiada na pytania dotyczące jego poglądów na matematykę i życie ze szczególnym uwzględnieniem okresu Solidarności i przemian ustrojowych lat 80. i początku lat 90. ubiegłego wieku, w których brał czynny udział.
Darmowy fragment publikacji:
Joseph Traub and Carnegie Mellon
BK: How did you contact Joe Traub?
HW: In 1969, when I worked as an assistant, I attended a summer
school in Gdańsk, where I had a short presentation. I said that
I was interested in nonlinear equations. That was when Stefan
Paszkowski referred me to J.F. Traub’s book from 1964 about
solving nonlinear equations.
BK: Thanks to Paszkowski, Joe Traub’s name appears for the ﬁrst time. . .
HW: Yes. After I returned to Warsaw, I hastened to the library
on Śniadeckich Street and that is where I read Traub’s book.
It was the best mathematical library in the whole Eastern bloc
– there you could ﬁnd all of the books published in the West.
People from East Germany, Czechoslovakia, Bulgaria came to
this library. It was diﬃcult to check anything out there, because
there was usually only one copy of any book, so a visitor had
to read the books on the spot. There I saw that I was able to
prove several Traub’s conjectures. The natural consequence of
this was my letter that I sent to Traub. I wrote that I knew the
answers to some of the questions that he posed in his book from
1964, and the answers are this and this, etc. At the time, letters
from Poland to the United States took about four weeks to arrive,
and indeed – after more or less two months I received a response.
Traub wrote that this is indeed fascinating, and he would like to
receive my paper. If I would like to submit it for publication, he
8. Joseph Traub and Carnegie Mellon (cid:72) 61
is on the Editorial Board of SIAM Journal of Numerical Analysis,
and he would love to handle the article. I sent the article to
him after writing an English version. Independently, I received
a letter from him with the information that in May of 1973 he
would be organizing a conference at Carnegie-Mellon University
in Pittsburgh and he was inviting me to participate and oﬀering
to cover the costs of the journey and the stay.
I received this letter in March, maybe. It was completely
impossible, even with the best of eﬀorts and intentions, to get
a passport in two months – at the time nobody kept passports
in desk drawers. American visas were also diﬃcult to come by.
I wrote back that it is unrealistic for me to make it in May. So then
Traub wrote me back – again, two months later – that I should
show up whenever I could. He sent me an oﬃcial invitation
without specifying the time period, with a declaration that all
costs would be covered. This invitation made Professor Turski
very happy, because it went along with his plan to build in
Warsaw a world-class center for applied mathematics. He assured
me that he would get me a passport. From what I remember
my visa was organized by Carnegie-Mellon, by contacting the
consulate in Warsaw. And so on September 16, 1973, I came to
the United States for the ﬁrst time. I remember the date, because
on September 17, 1973, Poland was playing the decisive soccer
match against England in the 1974 World Cup qualiﬁcations.
That was the famous match at Wembley Stadium.
By the way, I had no idea that I would have trouble ﬁnding out
the results of the match. I tried for several days – the American
newspapers said nothing, the television was only covering base-
ball – nothing about soccer! Finally, in the main library of the
university, where they brought newspapers from Europe, after
a few days, I saw that the result was 1:1. Until this day, I don’t
understand why soccer has not become popular in the United
States. Many fans of soccer, who came to the United States from
Europe and South America, could not inspire enthusiasm for the
game. I saw at least two serious attempts to popularize soccer
in the States. Pelé was responsible for the ﬁrst attempt, and the
second was led by David Beckham. Both attempts failed.
62 (cid:72) On mathematics, complexity, and life
BK: How long was your ﬁrst visit to Carnegie Mellon University?
HW: The invitation didn’t specify a length of time, and when
I arrived, the university oﬀered me a year-long stay. I refused, ﬁrst,
because I came without my wife Grażyna, and second, because
I didn’t want to create an awkward situation for Professor Turski.
So I oﬀered to stay until Christmas (this was in 1973), and maybe
to return the following year with Grażyna. Sometime later – after
I returned to Poland with an invitation for the 1974–75 academic
year, I spoke with Professor Turski. He thought that a trip with
my wife would be diﬃcult to arrange and tried to convince me to
go even without Grażyna. I did not agree, and luckily Professor
Turski was able to organize passports for both of us. We wanted
to take advantage of Grażyna’s stay in the United States in order
to consult some gynecologists.
Let’s digress for a bit and talk about the Traub marriage: in
1974, before we left for the United States, Joe Traub with his
wife Pamela were attending an IFIP Congress in Sweden. On their
way back, they came to visit Poland for a week. You met them at
the time as well. I wanted to show them Cracow and Zakopane.
We took a train to Cracow, and from there we hired a taxi for
a whole day to go to Zakopane. The taxi driver charged us what he
thought was a lot of money, but the dollar was worth so much at
the time that it amounted to less than twenty dollars. The driver
drove like a madman along ‘Zakopianka,’ which is the main road
to Zakopane, with each cigarette he lit, he tilted his head and the
car veered oﬀ the road to the left, and Joe cried: “He’s going to kill
us!” “I’ve been driving like this for thirty years, man, why would
we have an accident today?” the driver responded. I showed our
guests the famous mountain lake called Morskie Oko (The Eye
of the Sea). We tried to go to see the legendary Black Lake, but
there it was Pamela who was crying – she was afraid of heights.
Pamela fell in love with sheepskin coats in the town of Nowy Targ
and she bought one for a comical price for her of some twenty
or so dollars after converting from zlotys. Due to the duty fee,
the sheepskin stayed in Poland. We brought it to Pamela when
Grażyna and I came to the States. The pictures we took at the
8. Joseph Traub and Carnegie Mellon (cid:72) 63
Hala G ˛asienicowa in the Tatra Mountains during the Traubs’
visit to Poland hung for years in Joe’s oﬃce in New York.
Let’s go back to my time in the United States in 1973. At ﬁrst,
I had many ‘newcomer’ adventures. I was sent on this journey
without a single dollar in my pocket. I smuggled through ten
British pounds which I received from my friend Marcin Majda.
I ﬂew on the Warsaw – New York City route with Poles who had
emigrated out of Poland. One of them was very surprised that
I didn’t have any money. He took two dollars out of his pocket,
and lo and behold, I was the proud owner of two dollars! In New
York I had to change airports from Kennedy to La Guardia. Some
woman oﬃcial realized that I didn’t have any money and she gave
me a free bus ticket. So not spending a penny I found myself at
the La Guardia airport, and from there I ﬂew to Pittsburgh. I sat
next to a man whose heritage was Polish. He didn’t speak Polish,
but he liked Poles. His question gave me chills: “What will you do
if nobody is waiting for you at the airport?” The expression on my
face must have told him that I am not at all prepared for something
like that. “Don’t worry,” he said, “I’ll take you to my home.” Luckily,
there was somebody waiting for me at the airport – my later friend
and colleague H.T. Kung, a Chinese American man from Taiwan
who had received his PhD a few months before I came.
BK: Who was his thesis advisor?
HW: Traub. Kung’s thesis was formally in pure mathematics.
He began his studies at the University of Washington in Seattle,
where Traub taught for only a year. Later, Traub was oﬀered
the position of head of the Computer Science Department at
Carnegie Mellon, and he took Kung with him. Kung ﬁnished his
PhD in Pittsburgh in the Department of Mathematics.
As I already said, Kung was waiting for me at the airport.
He mistook my new friend from the ﬂight for me. I was well
dressed by my wife, while my friend from the plane looked miser-
able. He ﬁt perfectly an American’s imagination of what somebody
from Eastern Europe would look like. Kung drove me to the hotel
quickly and without any problems – from what I remember with
a cracked windshield.
64 (cid:72) On mathematics, complexity, and life
I met Traub the next day. That’s all very well, but I still only
had two dollars and ten pounds. I gently informed Traub. There
was some resulting chaos (“how could they let you out without
any money?”), there was a collection, and I became the proud
owner of ﬁfty dollars. Then there was my ﬁrst encounter with
a bank: I asked the lady at the window “are you free?” instead
of “are you open?” She punished me with a glare. The ﬁrst time
I opened a bank account – “saving” or “checking account”? – this
was all very new for a ﬁrst time newcomer from Poland.
The next day I had a seminar, which stretched out through
the next two meetings. There were questions and discussions and
so forth. I shared a room with Kung, who helped me very much,
among other ways – with the language. The ﬁrst letter came to me
at the beginning of my time in the United States – a letter from my
mom, sent from Poland before my ﬂight out, wishing me a good
stay. I also received an invitation to an annual party organized
by Traub, as head, for all of the department employees. That
is where I met Traub’s (second) wife, Pamela. Because Traub’s
book from 1964 was dedicated “to Susan,” I nearly came out to
Pamela with “nice to meet you Susan.” Kung with his wife also
tried to introduce me to local life in Pittsburgh.
Traub wanted to organize for the three of us – myself, Traub
and Kung – writing a paper. Kung, I felt, after receiving his PhD,
was not too eager to take on this project. He managed to loosen
his bonds with Traub, and in the end only I remained as Traub’s
‘research mate.’ Later, Kung’s interests deﬁnitively went towards
hardware questions. He moved to Harvard and made a career
in the ﬁeld. The other person visiting Carnegie-Mellon was Leslie
Valiant. He tried to obtain a position at Carnegie-Mellon when
I was there, and he did not receive Traub’s support, which Traub
later regretted. One of Valiant’s weaknesses, according to Joe, was
his poor American English. Valiant was British, after all. Later,
Valiant went to Harvard and in 1987 received the Nevanlinna
Prize in Mathematical Aspects of Information Sciences.
BK: Since we are already on the subject – Kung seemed like a very
talented individual who knew exactly as much mathematics as he needed
for his work.
8. Joseph Traub and Carnegie Mellon (cid:72) 65
HW: He was a product of the American schooling system, which
is, in my opinion, very bad. Of course, people who learn on their
own and are by nature autodidacts are not hindered by this
system – however, the system does not in fact teach anything.
I met many famous mathematicians in the United States who
did not know fundamental things. One of these, a man who had
very good results in approximation theory, I met the following
year. He did not know what a Jacobi matrix is – up until this
point, he had only worked with one-variable functions.
BK: We only learn what is useful to us at any given moment. A pragmatic,
HW: That’s how it is.
BK: What kinds of impressions did you have of Pittsburgh as a city?
HW: I knew that Pittsburgh was an industrial city, so I antici-
pated that the stay would be like going to Silesia, for example.
In the United States Pittsburgh has the reputation of being dull,
dirty, and industrial. And indeed, that’s the way it was in the
60s. However, when I arrived it wasn’t so bad anymore. At the
beginning of the 70s, there were eﬀorts to clean up the city, to
depollute the air and the water, and make the whole city more
attractive as a whole. These eﬀorts were successful. The campus
of Carnegie Mellon University was very green – it was located in
Moreover, the city turned me over to a ‘host family.’ My hosts
were Poles by ancestry. They were part of an organization that
took care of foreigners. They invited me for weekend outings,
family gatherings, parties, etc. The city was also very helpful
during my second stay at Carnegie Mellon. It would inform me
about various cultural events and made buying tickets easier.
Do you remember when we went together to watch Jesus Christ
BK: Of course I remember! I also remember Jerzy Grotowski’s visit at
Carnegie Mellon. There were lots of people who came. Grotowski spoke
in French with an English translator. He explained how he formed his the-
atre. An African-American woman came and began to demonstrate his
66 (cid:72) On mathematics, complexity, and life
theories on the spot. She appeared on the stage, interrupting the lecture,
and began to perform Grotowski’s exercises. . .
HW: Somebody yelled, “who’s in charge?” and the woman was
asked out. Pittsburgh also hosted our Polish volleyball team.
BK: Yes, at the time they were world champions, even though they had
not yet won gold in the 1976 Olympics in Montreal.
Did the Polish authorities contact you during your stay?
HW: At some point, somebody from the Polish Embassy called
me and asked to meet. He came to my oﬃce and told me straight:
“I am from the security division” – as he called it! He asked me
if I had not been involved in any research related to military,
and I told him, factually, that I had not. It turned out that he
was interested in research in the realm of proof theory. This
theory was being studied by, for example, Jacek Blikle, professor
of informatics and inheritor of the very famous sweets factory.
But that has to do with proving theorems, not commanding an
army!∗ I tried to explain this diﬀerence to him. He agreed that
several people had indeed told him that he had misunderstood
the name of the theory. In the end, he gave me a piece of paper
with his contact number: “We have a Baltona store in Washington.
If you are ever there, please come. Everything is cheaper.” Indeed,
a few months later I was in Washington, invited there by Stewart
and Rheinboldt of the University of Maryland, and I went to
this Baltona store. They didn’t want to sell me anything, so
I gave the woman the piece of paper I had received with this
man’s telephone number. She called the number and handed
the phone to me. The man was pissed oﬀ! “What are you doing!
You are exposing me! You have no idea what world you live
in. . . ” After that phone call, however, I was able to buy some
things in the store.
I had another adventure with the Polish Security that had to
do with Kung. In 1976, Kung was a Taiwanese citizen with an
American green card, visiting France every once in a while to
∗In Polish, the words for ‘proving’ and ‘commanding’ are the same, hence
the confusion on the part of the man from the security division (translator’s
8. Joseph Traub and Carnegie Mellon (cid:72) 67
collaborate with French colleagues. I had the idea to invite him
to Poland. This was impossible to do unoﬃcially, because Poland
had no diplomatic relationship with Taiwan, but I felt that I could
cheat the system somehow. At the time, I was the vice-director
of the Institute of Informatics at the University of Warsaw and
I sent Kung an invitation. It could have been interpreted as
an unoﬃcial invitation, but it was signed ‘Vice-Director of the
Institute of Informatics at the University of Warsaw.’ Kung applied
for a visa at the embassy in Washington, and the invitation was
treated as oﬃcial. Unfortunately, things did not work out well.
The embassy contacted the Ministry of Foreign Aﬀairs asking if
they had any such invitation in their records. They did not, so
they contacted the Foreign Aﬀairs Section at the University of
Warsaw. The oﬃcial there called me and asked: “Did the Institute
apply to invite Professor Kung?” All of this happened within 24
hours. I told the truth – I said this was my own, private, unoﬃcial
initiative. Chaos erupted! “What are you doing, sir?! You can’t do
things like that!” and so on, and so forth. Luckily, the oﬃcial from
Foreign Aﬀairs managed to calm everything down, explaining
that there had been a misunderstanding, and that I was an
inexperienced young man. Kung was refused a visa, and so it
was that he never came to Poland. I, in turn, was informed that
if that kind of situation ever happens again, I will face serious
BK: In Pittsburgh you met Professor Altman’s family, who you had known
during your time as a student at the University of Warsaw.
HW: I met Professor Mieczysław Altman in 1968, when I signed
up for his class on solving nonlinear equations. He never ﬁnished
this class – I think it only existed for one semester. The events
of March 1968 interrupted his classes and the Altman family
emigrated to the United States. Any contact with the professor
was cut oﬀ. Serendipitously, we ran into Professor Altman’s wife
Wanda during our ﬁrst longer stay at Carnegie Mellon, in Pitts-
burgh. Grażynka and I were shopping at the Giant Eagle market,
speaking in Polish, and suddenly a woman started talking to us
who turned out to be Professor Altman’s wife.
68 (cid:72) On mathematics, complexity, and life
BK: It’s a small world, after all. . .
HW: Wanda wholeheartedly took up the task of looking after us
during our stay. We often met with her in Pittsburgh, and then
the whole Altman family visited us in New York. At the time, the
Altmans were separated – Mieczysław was working at a univer-
sity in Louisiana, and Wanda was a medical doctor who had
succeeded in getting certiﬁed to work in Pennsylvania. You could
see that Wanda missed Poland a lot – in her presence we couldn’t
criticize our country in any way. The Altmans’ son, Tomek, was
studying at the University of Pennsylvania. He was interested in
mathematics and numerical methods. I once conducted a discus-
sion – via Tomek – with a lecturer in numerical methods at his
university on applicability of Gaussian elimination for matrices
larger than 30. Tomek’s lecturer adamantly claimed that Gaus-
sian elimination cannot be applied to these kinds of matrices.
In the end, however, he agreed with me that – in fact – it could. . .
We saw the Altmans’ daughter, Basia, in New York many
times. Tomek completed a PhD in computational mathematics
and then worked at the University of Kentucky in Lexington,
where there were many Poles, and then in Denver, Colorado.
In the 80s, Professor Altman visited Poland – at the Banach
Center, the janitor greeted him with the words: “Good morning
professor, we haven’t seen you in a long time.” To this day, I have
contact with the Altman family from time to time.
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