Angel Raichev, a student at the 125^th Boyan Penev High School in Sofia, has invented his own theorem, with which he was selected by the Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences to participate in the prestigious summer research programme for students in the United States (RSI).

Angel Raichev impressed the jury from the Bulgarian Academy of Sciences (BAS) with his project "L-polymino". He himself admits that he has always liked numbers more than letters, and he has been seriously involved in mathematics since the 3^rd grade.

The quota for participants from Bulgaria in the summer research programme for high-school students in the United States is only for two participants - one in mathematics and one in computer science, as the candidates this year were dozens.

The training of the gifted students from around the world, who will work on projects under the guidance of prominent scientists, will take place in the summer of 2021 in Boston and will last six weeks.