Four mathematicians have been awarded prestigious Fields medals, including Ukrainian Maryna Viazovska, the International Mathematical Union jury said on July 5.
Viazovska is only the second woman to win the prize, considered the equivalent of a Nobel Prize for mathematics.
She accepted the award at a ceremony in Helsinki as war raged in her home country.
The other winners were French mathematician Hugo Duminil-Copin of the University of Geneva; Korean-American mathematician June Huh of Princeton; and British mathematician James Maynard of the University of Oxford.
The Fields Medal is awarded every four years to mathematicians under 40.
Maryam Mirzakhani , an Iranian-born professor at Stanford University, was the first woman to receive the prize for her work in 2014. She died of breast cancer in 2017.
Viazovska has been a professor at the Ecole Polytechnique Federale de Lausanne in Switzerland since 2017.
She was awarded for her work in sphere packing -- a problem first posed by German astronomer and mathematician Johannes Kepler nearly 400 years ago.
The International Congress of Mathematicians, where the prize is awarded, was initially scheduled to be held in the Russian city of St. Petersburg -- and opened by Russian President Vladimir Putin.
Earlier this year, hundreds of mathematicians signed an open letter protesting the choice of the host city. After Moscow invaded Ukraine in late February, the event was moved to the Finnish capital.