Mismatch

Z←L≢R returns a Boolean scalar identical to ~L≡R.

L and R are both arbitrary arrays.

Z is a Boolean scalar whose value is 1 if the two arguments differ in any respect be it depth, rank, shape or value, and 0 otherwise.

For example, in origin-1

      ''≢⍬
1
      1 2 3≢⍳3
0