ディオファントス近似
In his 1967 paper, "Disjointness in ergodic theory, minimal sets, and a problem in Diophantine approximation", Furstenberg introduced the notion of ‘disjointness,’ a notion in ergodic systems that is analogous to coprimality for integers. The notion turned out to have applications in areas such as number theory, fractals, signal processing and electrical engineering.