# `⍥` — Over

Keys: `Alt-1 o`

`f⍥g Y` is `f(g Y)`.

``` bpl
+/⍥, [1 2⋄3 4]   ⍝ 10
```

`X f⍥g Y` is `(g X)f(g Y)`.

``` bpl
1 2 +⍥≢ 3 4 5      ⍝ 5ₓ
```

Compare [After](after.qmd), which transforms only the right argument.

## Inverse

With an argument fixed, `X(f⍥g)⁻¹Y` inverts `f` with `g X` fixed, then
applies `g⁻¹`.

``` bpl
1(+⍥⊽)⁻¹8   ⍝ 3
```