I have a separate .tex file for a list of symbols. They aren't nomenclature because I included more information than simple definitions. (I have 3 columns.) When I use \include{symbols} the header on the previous "chapter" is printed. I followed the answer to this question: Nomenclature as a chapter but as I'm not using the nomencl package it didn't work. Is there a similar command to \include?

Edit:

The answer below as well as the tip from lockstep solved my problems, anyway just to complete my question my base file looks like:

\documentclass[a4paper,12pt,twoside]{book}
\include{formatAndDefs}
\begin{document} \include{TitlePage}
\dominitoc
\pagenumbering{roman}
\cleardoublepage
\tableofcontents
\listoffigures
\listoftables
\cleardoublepage
\markboth{\nomname}{\nomname}
\printnomenclature[5em]
\include{symbols}
.
.
.
\include{chapter1}
.
.
.
\end{document}

-
\include has nothing to do with headers. Show a minimal example that demonstrates your problem. –  Ulrike Fischer Nov 20 '12 at 13:12
@UlrikeFischer I've edited my question –  ziulfer Nov 20 '12 at 15:03
@lockstep Thank you very much!!! I've just defined the argument in \markboth and it worked as it should!! –  ziulfer Nov 20 '12 at 15:06
There is always the \input instead of using \include. –  Peter Grill Nov 20 '12 at 20:12

As you're not using the nomencl package, it could well be that \nomname (in the arguments of \markboth) is undefined. Replace it with "List of Symbols":

\cleardoublepage
\markboth{List of Symbols}{List of Symbols}
\include{symbols}

-
thank you once again!! –  ziulfer Nov 20 '12 at 15:15

\include always starts a new page. unless the file begins with a command (like \chapter) that applies a new format and resets the running heads, the headers will simply continue from the preceding chapter.

if you really want no header, perhaps putting \thispagestyle{plain} would give you a reasonable result. unless you have redefined the plain style (or are using a document class that has done so), it will center the page number at the bottom of the page, and omit headers entirely.

if your list of symbols continues for more than one page, the second and following pages will also contain the running head values from the preceding chapter. you should use \markboth{...}{...} to establish the values that you do want for the headers.

-
The answer to the question the OP linked to uses \markboth. –  lockstep Nov 20 '12 at 13:59
Thank you. As @lockstep mentioned I've already tried to use \markboth but it was undefined, once defined, it worked. –  ziulfer Nov 20 '12 at 15:05