CHINA TOPIX

Updated 10:35 AM EDT, Thu, Apr 18, 2019

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‘Slow Witted’ Chinese Math Genius Amazes with Carmichael Number Formulas

Slow witted?

(Photo : China Daily) Math genius Yu Jianchun

A 33 year-old parcel delivery worker from the mountains of Henan who describes himself as "slow witted" has formulated a more efficient way of identifying "Carmichael numbers."

Yu Jianchun developed five formulas for the Carmichael numbers, which are pseudo-prime numbers that occur as positive integers some 255 times per 100 million. He's also developed an alternative method to verify Carmichael numbers.

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Carmichael numbers complicate the task of determining true prime numbers, or numbers divisible only by the number one and by itself. They play an important role in computer science and information security.

"I made my discoveries through intuition," said Yu. "I would write down what I thought when inspirations struck about the Carmichael. I have hard work and make a hard living, but I insist on my studies."

Yu sent his solutions to Dr. Cai Tianxin, a math professor at Zhejiang University, along with solutions to four other problems. He later presented his solutions to the public at a graduate student seminar at the invitation of Cai. Yu's solution to complex math problem has also amazed Chinese academics.

Yu said it took over eight years of writing letters to prominent Chinese mathematicians to get any recognition for his talent. 

"It was a very imaginative solution," said Cai.

"He has never received any systematic training in number theory nor taken advanced math classes. All he has is an instinct and an extreme sensitivity to numbers."

Yu graduated from a technology training school in Zhengzhou, Henan province and hails from Xinxian county, a mountainous part of Henan. He admitted to having had little higher education but has a lot of interest in mathematics and spends almost all of his spare time studying math.

A migrant worker after graduation, Yu said he's always had a passion for numbers. His goal now is to find a wife.

Incredibly, Yu described himself as "slow witted."

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