Acute Accent (´)

𝔽´ 𝕩: Fold

Fold over 𝕩 with 𝔽 from right to left i.e. Insert 𝔽 between the elements of 𝕩.

𝕩 must be a simple list (1 = =𝕩).

       +´ 1‿2‿3
6

       1+2+3
6

       -´ 1‿2‿3
2

       1-2-3
2

𝕨 𝔽´ 𝕩: Fold With initial

Monadic fold, but use 𝕨 as initial right argument.

       5 +´ 1‿2‿3
11

       1+2+3+5
11

       5 -´ 1‿2‿3
¯3

       1-2-3-5
¯3