Etymology
Named after Kenneth E. Iverson, who introduced this notation in his programming language APL.
Noun
Iverson bracket (plural Iverson brackets)
(mathematics) A notation that denotes a number that is 1 if the condition in square brackets is satisfied, and 0 otherwise, i.e.
(where P is a true or false statement)
[P]=left{begin{array}{ll} 1 & text { if } P text { is true; } \ 0 & text { otherwise. } end{array}right.
转载地址：https://en.wiktionary.org/wiki/Iverson_bracket
