[Tex/LaTex] newline and italics added with \leq

math-modesymbols

Newbie question: Within the body of the text that I've inserted into a Journal's Latex Template, I don't understand why I get a newline and italicized font when I add the command \leq to generate "less than or equal to"…

Below is (1) the Journal's template preamble and (2) my text in the body of the document.

I'm using MacText/TexShop on MacOSx10.6

(1) PREAMBLE

\NeedsTeXFormat{LaTeX2e}[1995/12/01]
\documentclass[10pt]{bmc_article}    

% Load packages
\usepackage{cite} % Make references as [1-4], not [1,2,3,4]
\usepackage{url}  % Formatting web addresses  
\usepackage{ifthen}  % Conditional 
\usepackage{multicol}   %Columns
\usepackage[utf8]{inputenc} %unicode support
%\usepackage[applemac]{inputenc} %applemac support if unicode package fails
%\usepackage[latin1]{inputenc} %UNIX support if unicode package fails
\usepackage{times} %so today's date appears on each version
\urlstyle{rm}

\def\includegraphic{}
\def\includegraphics{}

\setlength{\topmargin}{0.0cm}
\setlength{\textheight}{21.5cm}
\setlength{\oddsidemargin}{0cm} 
\setlength{\textwidth}{16.5cm}
\setlength{\columnsep}{0.6cm}

\newboolean{publ}

(2) IN THE BODY OF THE DOCUMENT .tex

coefficients kappa: \leq 0.4 poor to fair; 0.6 moderate agreement.

in Typeset: this pdf reads

coefficients kappa:

<={italics}0.4poortofair;0.6moderateagreement

Best Answer

From your edited post, the problem seems to be that you have not entered math-mode.

Short answer.

Try writing the following in your document body:

coefficients kappa: $\leq 0.4$ poor to fair; $0.6$ moderate agreement.

Note the dollar signs $.

Long answer.

When you write LaTeX with mathematics in it, you will often switch between "text mode" (normal prose) and "math mode". This is what the $ symbol does: switch from one to the other. Math-mode text is printed in italic text, but it is not typeset to look good as italic text — it is typeset to look like good mathematics. (In a LaTeX document, compare the appearance of the results of \textit{italics}, which typesets the word "italics" in italics, and $not really italics$, which typesets that text in a slanted font as though it were a product of variables n, o, t, etc.)

LaTeX only wants to see the symbol \leq in mathmode, where it makes sense to it (because it is defined as a mathematical relation in the LaTeX source). So when it saw it, it complained good-naturedly about missing a $ symbol, and then assumed that everything that came afterwards was also in math mode until it reached the end of the document or another $ symbol. This will happen for many other commands, such as \sin (for the sine function), \sum (if you are doing summations), \kappa (which typesets the greek letter κ), and so forth.

In those cases where you really want italics, use \textit, as I suggested above. (Similarly, bold-face text is \textbf, small-caps text is \textsc, and so forth.) There are other ways of including math (when you want a big equation), in which case you should look up the AMS math environments, align, gather, and so forth.

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