3

I'm very new to LaTeX, and have never been very good with computers, so apologies for not knowing how to post questions on here properly or missing out anything important.

I have this:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[F_f=\{z\in \mathbb{\hat{C}}:(\vert f^n(z) \vert) is bounded\}\]
\end{document}

"is bounded" comes out in italics and I'd like it to look like normal text (as in text not in $$ or \[\] signs. Any help would be appreciated.

And I realize that I've got lots of \ signs missing, they don't seem to show up.

4
  • 2
    Use: \text{ is bounded}. Mar 23 '14 at 16:56
  • Use \text{ is bounded} and be happy.
    – Sigur
    Mar 23 '14 at 16:56
  • 3
    Better yet, \{z\in\hat{\mathbb{C}}:\text{$(\lvert f^n(z)\rvert)$ is bounded}\}
    – egreg
    Mar 23 '14 at 16:58
  • @egreg You should make that an answer. Jan 18 '15 at 13:48
4

I'm not fond of long set descriptions like this, so I'll show also how I'd describe the set.

The trick is to temporarily go in text mode. However the input

(\lvert f^n(z) \rvert) \text{ is bounded}\}

is awkward and I find it much better to use \text for the whole description, getting back in math mode inside it.

\documentclass{article}
\usepackage{amsmath,amssymb}

\begin{document}
Define
\[
F_{f}=\{z\in \hat{\mathbb{C}}:
  \text{$(\lvert f^n(z) \rvert)$ is bounded}\}
\]
and prove something about this.

We define $F_{f}$ as the set of $z\in\hat{\mathbb{C}}$ such that the 
sequence $(\lvert f^n(z) \rvert)$ is bounded.
\end{document}

Note that the correct syntax is \hat{\mathbb{C}} and it would be meaningful to have something like

\newcommand{\numberset}[1]{\mathbb{#1}}
\newcommand{\nC}{\numberset{C}}
\newcommand{\hnC}{\hat{\nC}}

so we can write z\in\hnC and don't bother with formatting instructions in the document body.

Note also that \lvert...\rvert is the correct usage when amsmath is loaded.

enter image description here

7
  • 1
    Now that you are at it, I think it would also be great \DeclarePairedDelimiter\set{\lbrace}{\rbrace} and \DeclarePairedDelimiter\abs{\lvert}{\rvert} and use them appropriately.
    – Manuel
    Jan 18 '15 at 14:10
  • @Manuel I don't agree about \set; for \abs it could be. However it's outside the scope of the question.
    – egreg
    Jan 18 '15 at 14:19
  • @egreg Is there a particular reason for writing, say, \[\text{$f$ is}\] instead of \[f\text{ is}\]? (Personally I like your way of doing is, so I'm just curious.) Jan 18 '15 at 15:07
  • 1
    @SvendTveskæg I find it awkward to have f\text{ is...}: \text{$f$ is...} is clearer and there's no risk of forgetting spaces. The clause is the complete $f$ is....
    – egreg
    Jan 18 '15 at 15:09
  • 1
    @SvendTveskæg Under normal settings, no.
    – egreg
    Jan 18 '15 at 15:11

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