Y must be a Boolean array.  X must be a Boolean array.  R is Boolean.  The value of R is the truth value of the proposition "not both X and Y", and is determined as follows:

             X   Y     R
      
             0   0     1
             0   1     1
             1   0     1
             1   1     0

Example

      (0 1)(1 0) ⍲ (0 0)(1 1)
 1 1  0 1