How to remove spacing after colon in math?

Questions
1

This feels like a silly question, but… $u[:n]$ renders like this:
image. What is the most elegant way to remove the spacing between : and n?

1 Like
2 
#show math.equation: it => {
  show ":": math.class.with("normal")
  it
}

$u[:n]$

image

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3

Thanks! Not sure how I managed to miss it in the docs…