1. 恒等运算符：icon 图标 | identity operator 恒等运算符 | ignore 忽略
2. 恒等算子：identity map 恒等映射 | identity operator 恒等算子 | identity permutation 恒等排列
3. 恒等算子;单位算子：单位方阵 identity matrix | 恒等算子;单位算子 identity operator | 一致路径 identity path
noun
1. an operator that leaves unchanged the element on which it operates
e.g. the identity under numerical multiplication is 1
Synonym: identity identity element