The Fields Medal. Photo courtesy of Australian National University

Held every four years, the congress, where the Fields Medal is awarded, gathers researchers from around the world to share major advances and discuss the future of mathematics. The 2026 meeting is set for Philadelphia, the first time in four decades that the U.S. will host the event.

Led by Ila Varma, an associate professor at the University of Toronto, and Tarik Aougab of Haverford College, the petition calls for a boycott if the congress remains in the U.S. It points to conflict in the Middle East, immigration enforcement measures and travel restrictions that, in the organizers’ view, clash with the ICM’s mission of promoting international unity among mathematicians.

"Mathematicians across the world recognize that the U.S.'s war on Iran, war on immigrants, and violent foreign policy are fundamentally incompatible with the principles of free and open science," Aougab said in a statement cited by Times Higher Education.

They also said U.S. immigration crackdown has created uncertainty for international scholars traveling to the country for research and conferences. Some researchers have already chosen not to attend events in the U.S. due to fears of detention or deportation, concerns that have spread across the global academic community.

As of Apr. 14, some 2,126 mathematicians from 75 countries, including 73 former ICM speakers, had signed the petition.

The IMU said holding the congress in person in Philadelphia is "especially important" at a time when science faces "serious challenges." The organization added it is committed to providing a safe and welcoming environment and has arranged for all sessions to be recorded and made available online.