# Cahit Arf: The Man Who Popularized Mathematics in Turkey

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*In the field of mathematics, Cahit Arf is among the first names to come to mind, not only in our country but all over the world. Arf has led many young people to choose the field of mathematics, even though some of them may not be aware of his influence. Arf has put much effort into changing the perception of mathematics and science in Turkey. But how many people know about Arf, whose portrait is on the 10 Lira banknote they handle every day?*

Cahit Arf was never tired of working, never lost his hope of changing the perception of science and continued his work on mathematics at TÜBİTAK’s Marmara Research Center until his death. The fact that students exposed to the learn-by-rote education system are unable to discover the beauty in mathematics, develop their personal curiosities and get to know the stories of our esteemed mathematicians causes the public interest in not only mathematics but all the basic sciences to be dwindled.

**Cahit Arf has played an important part in my choice**

Like many people, I used to have the opinion that mathematics was a hobby for people who had no other worries in life. I came across Cahit Arf during the years when the banknotes were redesigned; I did some research on his life, and thought about the conditions of the time he lived in. Arf was lucky: His father sent him to France because the French franc lost value at the time and he believed an education in France would cost him less than one in Turkey. Except for such little fortunes that life has brought about, Arf is one of us. The moment I understood this, I thought, “Perhaps mathematics is not simply the occupation of those who have no worries”.

Later, without actually engaging in mathematics, I began to read things that would spark my interest in the field. As my grades in school gradually got higher, I had the feeling that “I can do it too”. As I began to reap the benefits of my work, I worked harder and got more and more curious. And even though my current undergraduate study in the field seems like it will not be easy, I am still curious. And Cahit Arf probably changed the course of my life.

I don’t exactly remember how, but I learned that Haluk Oral from our University’s Department of Mathematics was in contact with Cahit Arf. I both wanted to ask him about certain curiosities of mine regarding Arf, and wanted to commemorate Arf here, as I feel his work is still underappreciated. I would like to thank Haluk Oral for taking the time to answer my questions.

And here is our short conversation, which was very exciting for me…

**How did you meet Cahit Arf? Was it mathematics that brought you together?**

It was during 90s. I was working at the TÜBİTAK Marmara Research Center. We went to work together, and I got to know him through our conversations on our way. I visited him in his home a few times as well.

**People who have careers in such “heavy” fields as mathematics, physics or philosophy are usually regarded as standing outside society. Did Cahit Arf fit that definition?**

No, definitely not. He was the smartest man I knew. He didn’t only talk mathematics. He used to talk about the poetics of mathematics, about biology and history, and tell nice anecdotes.

**Working on mathematics takes much time. But as I understand, Arf found the time to improve himself in many fields…**

You don’t need to work 15 hours a day to become a good mathematician. What you need to do is spend quality time working, and that’s what he did. That kind of focused long time work is needed when you’re learning a subject for the first time. After such learning, I believe you need to spend quality time to learn other aspects of life too…

**Mustafa İnan had as good a mathematical education as a mathematician, even though he was a civil engineer. Do you believe that caused an unspoken rivalry between him and Cahit Arf?**

The two were very good friends, and they have even worked together. Arf always spoke about İnan as a friend. There is no rivalry between scientists. Nothing is kept hidden in science.

**We know about your interest in literature. Do you think we may read your biography of Cahit Arf one day, similar to Oğuz Atay’s “The Novel of a Scientist”, which he wrote for Mustafa İnan?**

No; first of all, novels and biographies are not in line with my way of writing. It would be a task beyond me to write such a work on Cahit Arf. That book was Oğuz Atay’s TÜBİTAK project, and he mentions Cahit Arf often. In short, I couldn’t do it even if I wanted to.

**Do you believe Cahit Arf changed the perception of mathematics in Turkey?**

Was there any perception of mathematics for him to change, to begin with?!

**Cahit Arf’s Contributions to Mathematics**

- Arf’s work on the solvability of synthetic geometry problems with a ruler and compasses, and his work on the invariants that emerge in the classification of quadratic forms of objects resulting in the “Arf Invariant”, “Arf Closure” and “Arf Rings” brought him recognition in the world of mathematics.
- Arf Has made essential contributions to mathematics in various fields such as algebra, number theory, elasticity theory, analysis, geometry and engineering mathematics, resulting in structured and lasting work.
- The “Hasse-Arf Theorem” is among his significant contributions to the literature of mathematics.