A senior university lecturer from Bosnia's northern city Banja Luka has solved a math problem that seemed to have no solution – for decades.

31-year old Nebojsa Djuric got familiarised with what is known in the scientific world as the Inverse problem of the Sturm-Liouville-type with constant delay in 2016 and he decided to study it thoroughly. Once he realised that the issue was with an integral operator, he made a huge step towards the goal.

“When I started studying this integral operator in detail, I came to understand the essence of the problem and it helped me construct a counter-example, which eventually dismissed the hypothesis of the uniqueness of the solution,” explained Djuric, a lecturer at the University of Banja Luka.

According to him, the world-renowned mathematicians accepted his theory.

“What followed was a procedure for the reviewers to assess the work, and we had eight reviewers who are the best experts in this field doing it. They agreed after two months this was correct and the first version of this paper was published officially on October 30,” Djuric told N1.

His results were published in one of the best journals on the SCI list in this field – the journal Applied Mathematics Letters, in the paper titled ‘On an open question in recovering Sturm-Liouville-type operators with delay’.

The 40-year old problem will contribute to further developments in science, particularly in aerodynamics, astrophysics, biophysics and economics.

Djuric is aware of the fact the status of science in the country and that it was put on the margins. However, he is not thinking about moving abroad. His plans are now focusing on finishing his PhD and publishing quality scientific papers.