Left Arrow ←

Dyadic Left Arrow means

    V ← 5 6 7
    (i(j k)) ← 4(5 6)
    sum ← +⌿
    product ← {×/⍵}
    inverse ← ⍣¯1

    V +← 1
    V[2] ← 0
    (⊃V) ← 2