GUWAHATI: Mathematician and head of computer application department of Assam Engineering College Bichitra Kalita, has claimed to have solved the famous 'Goldbach conjecture', one of the unsolved problems in mathematics, using a new technique called the graph theory. Propounded by German mathematician Christian Goldbach in 1742, the Goldbach conjecture says every even number greater than two can be expressed as a sum of two prime numbers (which are divisible by one and the number itself). Since 18th century, mathematicians across the globe have been grappling with the Goldbach conjecture, but to no avail. Kalita said mathematicians tried different ways to prove the conjecture right as well as wrong. "But none could arrive at a conclusion. So the idea remained a conjecture and could not become a theorem," Kalita claimed. After researching on the subject for over six years on the subject, he was able to prove that Goldbach conjecture was correct and that all even numbers can be expressed as sum of two prime numbers. "I've proved the conjecture by using the graph theory technique. This is an entirely new application. Graph theory is a vital subject related with branches like computer science, electronics, telecommunications along with various mathematical sciences," Kalita informed. Kalita's research work "Graph and Goldbach Conjecture" has been accepted by the department of mathematics of University of Chemical Technology and Metallurgy in Sofia, Bulgaria in July this year. The work will be published in the International Journal of Pure and Applied Mathematics, Kalita informed. A Research Guide under Gauhati University here, Kalita is also engaged in graph theory researches in theoretical computer science and various other mathematical problems.