Although there are a lot of questions on subscripts none of them are the same as this one (as far as I can find).

I want to write \min_ and directly under that I want to write p \in R^n, that's obviously the easy part. Then I want to write \| p \| \leq \Delta_k directly under p \in R^n (like a double subscript). I can get p \in R^n to go directly under \min but I do not know how to get \| p \| \leq \Delta_k directly under p \in R^n.

This is what I have just now


&\min_{p \in \mathbb{R^n}_{\| p \| \leq \Delta_k}} \\


This makes \| p \| \leq \Delta_k a subscript of {p \in \mathbb{R^n} but it does not lie directly under it as I would like. Any ideas would be much appreciated.

  • Is there a reason for using align with a single equation? Note that the trailing \\ will produce an unwanted empty equation (with its number).
    – egreg
    Mar 28, 2017 at 21:35

1 Answer 1


You are looking for \substack. (Also, \mathbb{n} does not give what I presume you want)

&\min_{\substack{p \in \mathbb{R}^n \\ \| p \| \leq \Delta_k}} 

enter image description here

(Look, Mom, I didn't use stackengine!)

  • 2
    Such a good boy.....
    – daleif
    Mar 28, 2017 at 17:38
  • 3
    @cameron You are welcome. I noticed that with the several questions you have asked on this site, you have never "accepted" an answer. The way the site is supposed to work is that, of the many answers you may get to a given question of yours, if one of the answers properly answers your query to your satisfaction, you can accept that answer by clicking on the check mark to the left of that answer. That indicates to other readers that you found that particular answer the most helpful to your question. Mar 28, 2017 at 17:38

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