How to add a short text in math-mode keeping spaces between words

Question

I am writing the following:

$$p(Z_{n+m}=i for some m> 0|Z_{n}=i)=1$$

Compiling, the spaces between the words "i for some m" are removed giving as a result "iforsomem"

How can I prevent this?

Note that I cannot write something like

$p(Z_{n+m}=i$ for some $m> 0|Z_{n}=i)=1$

because I want it centered horizontally

Thank you for your help!

Answer 1

You need to do

\usepackage{amsmath}

in your document and then you can type

\begin{equation*}
\text{$p(Z_{n+m}=i$ for some $m>0 \mid Z_{n}=i)=1$}
\end{equation*}