GreaterThan.aplf

 GreaterThan←{ ⍝ > monadic Join
     0::∆SIGNAL ⎕DMX
     0≠⎕NC'⍺':⍺>⍙LA ⍵
     ⊃⊃{,[⍺]/[⍺]⍵}/(⍳≢⍴⍵),⊂⍵
 }