The miraculous return after 50 years of wandering of the "bomb-smoke-stained" thesis

The thesis of special value to the world mathematics of Professor, Doctor of Science Hoang Xuan Sinh has just been brought back to Vietnam after 50 years of "wandering". All thanks to the dedication of many great scientists in the country and the world.

One late autumn day in Hanoi, sitting in his office at Thang Long University, Professor - Doctor of Science Hoang Xuan Sinh (90 years old) pensively recalled the "conception" process and the "adventure" journey of his "brainchild" named Gr-Categories .

This is the only handwritten PhD thesis defended in France (and possibly in the world), the author is the first female mathematics professor in Vietnam.

Professor Hoang Xuan Sinh decided to pursue mathematics after graduating with a baccalaureate degree from Chu Van An High School (Hanoi). In 1951, her uncle took her to France to study at Toulouse University, where she chose to obtain a baccalaureate degree in mathematics.

Graduated from the University of Toulouse, she studied for a Master's degree in mathematics at the age of 26, following the program of the civil service recruitment exam for the Ministry of Education of the French Republic.

Ms. Sinh assessed that "this was a very difficult exam", so when she returned home, everyone noticed and favored her in choosing a work unit. After 10 days of thinking, she decided to choose Hanoi Pedagogical University and began her teaching career in 1960.

"As a university lecturer, teaching students knowledge to build the country, it is mandatory to do scientific research, update new information and knowledge. The doctoral thesis is the beginning of the scientific research journey," she recalled.

At this time, the number of PhDs in mathematics in Vietnam can be "counted on the fingers". The Faculty of Mathematics of Hanoi National University of Education has only one PhD, Professor Nguyen Canh Toan.

As head of the mathematics department, Ms. Hoang Xuan Sinh both encouraged each lecturer and each student to study and worked hard on her doctoral thesis.

"At a time when the country was in turmoil and hardship, with bombs and sacrifices happening every day, we just wanted to try our best every day, to use our strength to help the country - it was that simple," Ms. Sinh recalled.

With no instructor, no English books, no scientific community, the path to achieving a PhD was full of difficulties, making her "struggle forever".

In 1967, taking advantage of the opportunity when "20th century math genius" Alexander Grothendieck (French) came to Vietnam to teach for 3 weeks, Ms. Sinh made an appointment to meet him and asked him to guide her in her PhD thesis.

Professor Grothendieck accepted.

Upon returning home, this most extraordinary genius of the 20th century wrote Mrs. Sinh his first letter, giving her Vietnamese student the important topic and outline that she later built into Gr-Catégories .

During the 5 years Ms. Sinh wrote her PhD thesis, due to the difficulties caused by the war, the teacher and student only sent each other 5 letters. The letters had to be very short and it took 8 months for a letter to travel between France and Vietnam.

The second time he sent a letter to his students, Mr. Grothendieck advised, "If you cannot solve the problem of invertibility of objects in a category, then give up, do not do it anymore."

In response, Ms. Sinh admitted that she could not solve the problem, but she refused to give up. In the next letter, she said that she had "successfully reversed the objects." In her final letter, she announced that she had completed the outline of her PhD thesis.

"The success or failure of a thesis depends largely on the guidance of the supervisor. I will never forget the gratitude I owe to Mr. Grothendieck," said Ms. Sinh.

In those years, Hanoi Pedagogical University did not have a policy of allowing lecturers to take time off or reduce teaching hours to do scientific research. Professor Sinh taught 30 hours a week, and had to go to school almost every day.

During the day she taught, and at night she began writing her doctoral thesis by the light of an oil lamp in a damp, mud-walled house with grass growing up to her knees. The flickering lamp was covered, for fear of being discovered by enemy planes.

"My only worry was... mosquitoes. At that time, I just wished I had a flashlight so I could sit and read on the bed without worrying about the risk of fire like an oil lamp," Professor Sinh recalled.

Even though she writes her thesis from 9pm to midnight, she still wakes up early every morning and walks to school, 4km from her home. On rainy days, the female teacher walks barefoot, with her pants rolled up to her knees, along the flooded road, erasing the boundary between the pond bank and the road.

"If at night I wish there were no mosquitoes, then during the day I wish there were no planes passing by. Those were wartime wishes," she said.

Whenever the enemy was in the sky, the lecturer had to promptly take the students down to the trench right next to the classroom, without delaying even for a second, to avoid casualties.

In December 1972, when B52 planes flattened Kham Thien Street, Ms. Sinh and her students were doing an internship at Phu Xuyen B High School. In the sky, the planes roared terribly, but in the evacuation bunker, she was still working.

"B52s flew overhead, but I was still sitting there writing my thesis" - When the last wave of American bombs fell, she completed her PhD thesis. She sent it to Professor Alexander Grothendieck in 1973.

When Ms. Hoang Xuan Sinh said she wanted to go to France to defend her doctoral thesis, Prime Minister Pham Van Dong completely agreed. But some people were worried, thinking that "she would not return". The disagreement caused the thesis to be "suspended" for 3 years.

The President of the Vietnam Women's Union at that time gave convincing opinions, and Ms. Hoang Xuan Sinh was approved to go to France to defend her doctoral thesis.

Normally, handwritten doctoral theses are not accepted, but thanks to Professor Grothendieck's position, the council had more than 200 pages of Ms. Sinh's thesis typed for defense.

In May 1975, the Vietnamese female lecturer successfully defended her PhD thesis on Gr-categories at the University of Paris 7, in front of many professors, doctors, French scientists and overseas Vietnamese intellectuals.

This thesis plays an important role, greatly influencing the later development of the "n-Categories" theory, which is widely applied to quantum computers and applications in Topological Physics.

"It was the most glorious and happiest day of my life," she recalled.

Professor Hoang Xuan Sinh then returned to Vietnam to continue contributing to the development of the country's education. As for Gr-Catégories , her handwritten thesis has a special fate.

This thesis has never been published but many copies are kept in the libraries of many universities in France and Europe.

By chance, Professor John C. Baez, a famous scientist in the field of mathematics and computational science, read the handwritten thesis in French of a Vietnamese mathematician in a library in Germany. He decided to translate it from French to English so that more people could access this valuable work.

In 2022, Professor Ha Huy Khoi, former Director of the Vietnam Institute of Mathematics, was interested in Ms. Sinh's works and accessed the document archive of Professor Grothendieck at a university in Germany.

Here, he saw a handwritten thesis by Ms. Sinh, stamped by the University of Montpellier (France).

Mr. Khoi contacted Montpellier University to help find this thesis, but they informed him that all of Professor Grothendieck's documents had been transferred to Paris.

"I asked Professor Nguyen Tien Dung - who used to work at Montpellier University before moving to Toulouse University - to learn more about this thesis," Mr. Khoai recalled.

Mr. Dung then found Dr. Jean Malgoire - the last graduate student of Professor Grothendieck, along with a valuable handwritten thesis of Professor Hoang Xuan Sinh.

It was also Mr. Dung who personally brought this project back to Thang Long University, where Professor Hoang Xuan Sinh holds the position of Chairman of the Board of Directors, after half a century of "wandering".

This miraculous return comes from scientists both domestically and internationally who appreciate the quintessence and minds of humanity.

On the occasion of the 50th anniversary of the establishment of diplomatic relations between Vietnam and France and the 90th birthday of Professor Hoang Xuan Sinh (September 5, 2023), the University of Education Publishing House published the book Gr-Catégories including the full text of her PhD thesis.

Right at the beginning of the book, readers can see a handwritten part of the thesis that Ms. Sinh sent to Paris in 1973.

In the introduction to Gr-Categories , Professor Ha Huy Khoi shared that this work attracts the international mathematics community not only because of its rich content and important scientific results, but also because of its special birth.

In the world, there are probably not many PhD theses completed during wartime, when the supervisor and the doctoral student were tens of thousands of kilometers apart, communicating only by letters in wartime postal conditions.

Professor Sinh wrote more than 200 pages of his thesis by hand during the war, isolated from the international community, lacking information, documents, even the most basic means such as pens, paper, light, and sometimes even lacking full meals.

Mr. Khoi said this is a thesis with a "special fate", once forgotten, but now is the pride of the Vietnamese people about a woman, a great mathematician like Professor Hoang Xuan Sinh.

"Another rare thing is that the thesis's references only have 16 names, most of which are books, not articles. This proves that the results obtained in the thesis are not an expansion of existing results but a beginning," Mr. Khoi wrote.

The book also includes an article on the scientific content and significance of the thesis titled Hoang Xuan Sinh's thesis: Categorizing Group Theory by Professor John C. Baez.

"Ms. Hoang Xuan Sinh's results shed light on the problem of studying homotopy patterns of relatively "beautiful" spaces, such as CW-complexes," wrote Professor John Baez.

According to a representative of the Pedagogical Publishing House, this thesis has never been published, although many copies have been kept in the libraries of many universities in France and several European countries.

With 1,000 copies for the first edition, Gr-Catégories will be equipped for training faculties, mathematics research institutes in the country, libraries in France and many other countries.

In the following years, Professor Hoang Xuan Sinh devoted all her efforts and enthusiasm to building Thang Long University - the first private university in Vietnam. She wanted Vietnamese students to acquire knowledge that was ahead of the curve and to study in a serious and happy environment.

"Her life is a consistent journey of a patriotic intellectual and talented scientist: from the decision to leave a comfortable life in France to return to contribute to Vietnam's education during the fierce war years, the determination to reach the pinnacle of science in extremely difficult conditions, to the extraordinary efforts and determination to overcome many challenges and build the first non-public university in Vietnam's education system," wrote Professor Ha Huy Khoi.

At the age of 90, Professor Hoang Xuan Sinh still maintains the habit of waking up early, exercising, reading Vietnamese and French newspapers to grasp training trends in the country and the world.

She was so proud that Vietnamese students were so good at math that she once mistakenly thought that "of all professions, teaching is the easiest" and "of all subjects, math is the easiest".

In the current context, many people are no longer "interested" in pursuing mathematics and basic sciences, Professor Sinh hopes: "The economy must be strong and there must be adequate training for those who do mathematics, then scientists will wholeheartedly devote themselves to research.

Vietnamese people are very good, and I believe in our intellectual class."

Content: Minh Nhan

Photo: Son Tung

Design: Tuan Huy

10/25/2023 - 04:44

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