ISO 31-11 - WikipediaISO 31-11:1992 was the part of international standard ISO 31 that defines mathematical signs and symbols for use in physical sciences and technology. It was superseded in 2009 by ISO 80000-2:2009 and subsequently revised in 2019 as ISO-80000-2:2019.[1] It included definitions for symbols for mathematical logic, set theory, arithmetic and complex numbers, functions and special functions and values,
