↓ Drop r←x↓y

x must be a scalar or vector of integers. r is the result of removing from each axis of y as many elements as specified by the corresponding element of x. If x is positive, the first x elements are removed; if x is negative, the last x elements are removed; if x is zero, no element is removed.

Infix

If (an element of) x is nested, it must be a two-element vector, with the first item a nonnegative integer and the second item a nonpositive integer. In that case, the items removed on the corresponding axis are the first ⊃x and the last -⊇x.