⊢
⊢Y and X⊢Y return Y.
⊢Y
X⊢Y
Y
⊢1 2 ⍝ 1 2 1 2⊢3 4 ⍝ 3 4
Both arguments evaluate. ⊢ also separates a derived function from its argument.
(+∘1)⍣3⊢0 ⍝ 3