January 19, 2026Jan 19, 2026
KCNA Pyongyang Times

Developer of new mathematical theorem

Date: 24/02/2021 | Source: Pyongyang Times | Read original version at source

Ri Song Il, PhD and researcher at the mathematics faculty of the University of Sciences, is one of the competent scientists produced by the university.

Born into an ordinary farmer’s family in Kumya County of South Hamgyong Province, Ri had a special interest in math when he was young.

“Song Il was good at studies, especially math. His performance was always excellent enough to amaze me. So I would tell him to be a ‘doctor in mathematics’ in the future,” said Yun Myong Chun, his teacher at the then Songje Primary School in the county.

He enrolled at the University of Sciences, an institution for training talents in the basic science field, and majored in mathematics. After completing his university and postgraduate courses, he has been engaged in education and scientific research at its math faculty since 2001.

In those years, he independently presented “A new fixed point theorem in the fractal space” and authored more than 20 scientific papers of great academic significance including “A new idea to construct fractal interpolation curve”. He was awarded the February 16 Science and Technology Prize in 2016, the top honour which is conferred on top scientists and technicians in the DPRK.

He accepted the request from a famous international mathematics journal to be its critic in April 2016 and commented on dozens of papers published at different SCI-level magazines in different countries. He also examined some papers at the solicitation of several prestigious international journals and offered his opinions to the related magazines.

In particular, he developed a theory on nonlinear fractal interpolation for the first time in the world.

The theorem he presented in his “A new fixed point theorem in the fractal space”, which was carried in a renowned journal published by the royal mathematics association of the Netherlands in 2016, has been dubbed “Ri’s contraction mappings” and “Ri’s fixed point theorem” in the papers foreign scientists published in journals since 2018.

His 18-year-old son is now studying at his university.

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