Meanwhile : The $25 problem (KOR)

Lee Woo Young

The author is an HCMC distinguished professor at the Korea Institute for Advanced Study. 

An elderly man in a worn coat and thick horn-rimmed glasses slowly walked to the front of a conference hall. It was a break between sessions, yet no one left their seats. Participants watched in silence, wondering what problem he would present this time.

Approaching a chalkboard in the corner, he wrote down a mathematical problem and added a note beside it: Prize, $25. Attendees hurried to copy the problem. When doing this, his reward would sometimes increase depending on the difficulty. But the money was never the point. Solving one of his problems was itself an honor.

The man was Paul Erdos (1913–1996), an eccentric mathematician from Budapest who became one of the most prolific figures in the history of mathematics. Over his lifetime, he published more than 1,500 papers and collaborated with more than 500 co-authors.

Erdos was a talkative genius, but also disarmingly naive and often awkward in daily life. In the early 1950s, when the United States was gripped by anti-communist investigations, an immigration officer asked his opinion of Karl Marx. “A great man,” he replied. He was denied entry.

During screening for participation in the Manhattan Project, the U.S.-led nuclear weapons program, he was also rejected. Officials concluded that his talkative nature made it difficult for him to keep secrets. In hindsight, the outcome suited him. He devoted his life to finding good mathematical problems, sharing them with others and working together to solve them.

Erdos disliked staying in one place. A lifelong itinerant mathematician, he had no permanent home or family and traveled through more than 22 countries. At the age of 83, he died while attending a conference in Warsaw.

His final words left a quiet resonance: “I won’t become any more stupid.”

Erdos left behind a remarkable body of mathematical work, but perhaps his greatest legacy was something less tangible. By turning even difficult problems into a form of intellectual play, he inspired generations of mathematicians and students. His small prizes, modest in value, carried a deeper message that discovery itself was the true reward.

In the end, the measure of a life may not lie only in individual achievement, but in the curiosity and energy one awakens in others.

25달러 문제

이우영 고등과학원 HCMC 석학교수

허름한 외투를 걸치고 커다란 뿔테 안경을 쓴 노신사가 학술회의장 앞쪽으로 천천히 걸어 나왔다. 마침 휴식 시간이었는데도 불구하고 참석자들은 자리를 뜨지 않은 채 숨을 죽이고 그를 지켜봤다. 이번엔 또 무슨 문제를 낼까? 그는 회의장 한쪽 칠판으로 다가가 구석에 수학 문제를 하나 적었다. 그리고 그 옆에 상금 25달러라고 썼다. 참석자들은 부지런히 문제를 옮겨 적었다. 상금은 문제의 난이도에 따라 더 올라가기도 했다. 하지만 상금이 문제가 아니었다. 그의 문제를 풀면 그 자체로 큰 영예를 얻었다. 이 노신사는 바로 부다페스트 출신의 괴짜 수학자로 수학 역사상 가장 많은 논문을 쓴 폴 에르되시(1913~1996·사진)였다.

그는 수다쟁이 천재였으나 너무 순진하고 일상 행동은 극도로 서툴렀다. 1950년대 초 미국이 공산주의자 색출에 열을 올리고 있을 때, 미국 입국심사에서 심사관이 그에게 마르크스에 대해 어떻게 생각하느냐고 묻자 “훌륭한 사람이죠”라고 대답해 입국이 거부되기도 했다. 또 맨해튼 프로젝트(미국이 주도한 핵폭탄 개발 프로그램) 참여 면접 심사에서는 너무 수다스러워 기밀 유지가 어렵다고 판단되어 떨어지고 말았다. 그에겐 차라리 잘된 일이었다. 그는 오직 좋은 수학 문제를 찾고 문제를 함께 나누고 그것을 해결하는 데 일생을 바쳤다.

에르되시는 한곳에 머무르기를 싫어했고 평생 방랑 수학자로 집도 가족도 없이 전 세계 22개국 이상을 떠돌며 살았다. 그는 83세에 바르샤바에서 열린 학술회의 참석 중 숨을 거두었는데. 그가 남긴 마지막 말이 깊은 여운을 준다. “이제 더는 멍청해지지 않겠구나.” 그는 주옥같은 수학적 업적들을 남겼지만 아마도 그의 가장 큰 업적은 어려운 수학 문제에 유희를 담아 사람들을 고무시킨 것이리라. 실로 타인의 삶을 고무시키는 일이야말로 아름다운 삶의 표상이 아니겠는가.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.