⌿ — Reduce first
Monadic operator. Keys: Alt-Minus /
f⌿Y reduces the first axis.
+⌿2 3⍴⍳6 ⍝ 3 5 7S f⌿ Y starts each lane from the whole seed S on the right.
10+⌿3 2⍴⍳6 ⍝ 16 19Identities, ⍠K and errors follow /.