*δ*-box

## EnglishEdit

### NounEdit

- (analysis) A
*k*-cell which is a Cartesian product of half-closed intervals which are closed at their infima and open at their suprema, and such that the infimum of each interval is the coordinate of a given point (called "the corner" of the*δ*-box), and the length (i.e., measure) of each interval is equal to (the given value)*δ*.

#### Usage notesEdit

The "*δ*-box with corner at *a*" can be denoted symbolically as *Q*(*a*; *δ*). The 'δ' in "*δ*-box" can be subject without notice to substitution by any numerical expression, with the hyphen being replaced by a space.