identity function (identity mapping) The identity function iS: S →S, on a set S, is defined by iS(s) = s for all s in S. Identity functions have the property that if f: S → T is a function, then f∘iS = f and iT∘f = f.
identity function
数学辞典收录了4151条数学词条，基本涵盖了常用数学知识及数学英语单词词组的翻译及用法，是数学学习的有利工具。