Lower a constraint in the formula

Question

How can I add the term v<-{0,1}^n to the formula as in the screenshot?

   $  Pr_{v \leftarrow {0,1}^n} [ Fre(A,B,C) = Ja ] \leq \frac{1}{2} $

Edit Code:

\documentclass{article}

\usepackage{ amssymb }

\begin{document}

\begin{itemize}
\item[1.] $\underset{v \leftarrow {0,1}^n}{\Pr} \Big[ \texttt{Fre}(A,B,C) = \texttt{Ja} \Big] \leq \frac{1}{2}$

\end{itemize}
\end{document}

The code you've posted under the Edit Code: line won't compile unless one replaces \usepackage{ amssymb } with \usepackage{ amsmath }. (The macro \underset is provided by the amsmath package.) — Mico, Feb 02 '16 at 18:59

score 3 · Answer 1 · answered Feb 02 '16 at 18:51

I suggest you use the \Pr macro, which places its subscript argument (the "constraint") below rather than to the side when in displaystyle-math mode. For inline-style math mode, add \limits after \Pr.

A separate issue: use \mathtt for the letters that apparently need to be set in monospaced (aka "teletype") font face.

\documentclass{article}
\begin{document}
\begin{tabular}{ll}
inline-style math: use \texttt{\string\limits}&
$
\Pr\limits_{v\gets\{0,1\}^n} [ \mathtt{Fre}(A,B,C) = \mathtt{Ja} ] \leq \frac{1}{2} .
$ \\[3ex]
display-style math &
$\displaystyle
\Pr_{v\gets\{0,1\}^n} [ \mathtt{Fre}(A,B,C) = \mathtt{Ja} ] \leq \frac{1}{2} .
$
\end{tabular}
\end{document}

score 2 · Accepted Answer · edited Feb 02 '16 at 18:56

2

For example (some tuning is needed):

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
  \Pr_{v \leftarrow \{0,1\}^n}[ \operatorname{Fre}(A,B,C) =\operatorname{Ja} ] \leq \frac{1}{2} 
\]


\end{document}

If Fre and Ja are used more times, it would be wise to define them, e.g., \newcommand{\Fre}{\operatorname{Fre}}.

edited Feb 02 '16 at 18:56

egreg

1,121,712

answered Feb 02 '16 at 18:29

Przemysław Scherwentke

37,268

Benjamin · Answer 3 · 2016-02-02T19:00:39.727

0

An alternative to Przemysław's solution would be to use \underset{•}{•}.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\underset{v \leftarrow \left\{0,1\right\}^n}{\Pr} \Big[ \texttt{Fre}(A,B,C) = \texttt{Ja} \Big] \leq \frac{1}{2}
\]
\end{document}

I also tuned your original formula a bit to make it look a bit nicer.

edited Feb 02 '16 at 19:00

answered Feb 02 '16 at 18:37

Benjamin

4,781

I am trying to put it as item but I am getting this error ! Undefined control sequence. <recently read> \underset l.8 \item[1.] $\underset in the edit code. Do u know how can I fix it? – Mr Asker Feb 02 '16 at 18:45
Sorry, forgot to mention, that you need the amsmath package. – Benjamin Feb 02 '16 at 19:01
The \left and \right modifiers to \{ and \} aren't needed. In fact, they do exactly nothing but produce code clutter. – Mico Feb 02 '16 at 19:04
@Mico You are right. It's just a habit of mine, that I add \left and \right all the time, so I don't forget it when it is actually needed. – Benjamin Feb 02 '16 at 19:35
Please check out the postings Is it ever bad to use \left and \right? and “(” or “\left(” parentheses? for discussions of why using \left and \right habitually can be quite counterproductive. – Mico Feb 02 '16 at 19:56
Interesting. Thanks for making me aware of these questions. – Benjamin Feb 02 '16 at 20:00

Lower a constraint in the formula

3 Answers3