Iverson bracket

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.

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