Inter-universal Teichmüller theory

Inter-universal Teichmüller theory (IUT or IUTT) is the name given by mathematician Shinichi Mochizuki to a theory he developed in the 2000s, following his earlier work in arithmetic geometry. According to Mochizuki, it is "an arithmetic version of Teichmüller theory for number fields equipped with an elliptic curve".

Source: Wikipedia — Inter-universal Teichmüller theory (CC BY-SA 4.0)