I'm trying to get the negated \approx sign in LaTeX, as it is in here:
But the \napprox command does not work. Any ideas? Maybe it was switched to a new command? Or do I just need to include some package?
[Tex/LaTex] How to use the negated approximate sign
symbols
Related Solutions
I once proposed the following definitions
\newcommand\varpm{\mathbin{\vcenter{\hbox{%
\oalign{\hfil$\scriptstyle+$\hfil\cr
\noalign{\kern-.3ex}
$\scriptscriptstyle({-})$\cr}%
}}}}
\newcommand\varmp{\mathbin{\vcenter{\hbox{%
\oalign{$\scriptstyle({+})$\cr
\noalign{\kern-.3ex}
\hfil$\scriptscriptstyle-$\hfil\cr}%
}}}}
Example
\documentclass{article}
\newcommand\varpm{\mathbin{\vcenter{\hbox{%
\oalign{\hfil$\scriptstyle+$\hfil\cr
\noalign{\kern-.3ex}
$\scriptscriptstyle({-})$\cr}%
}}}}
\newcommand\varmp{\mathbin{\vcenter{\hbox{%
\oalign{$\scriptstyle({+})$\cr
\noalign{\kern-.3ex}
\hfil$\scriptscriptstyle-$\hfil\cr}%
}}}}
\begin{document}
$a\varpm b\varmp c$
\end{document}
As of biber 0.9.4/biblatex 1.6 you can define user-specified field and entrytype mappings. A special case of this is that you can map fields to null which essentially removes them from the input stream completely. So if for example, you want to just ignore all ABSTRACT fields in bibtex data sources (which are often the source of unwanted special chars when exported from automated systems), you can put this in your biber.conf:
<map>
<bibtex>
<globalfield>
ABSTRACT BMAP_NULL
</globalfield>
</bibtex>
</map>
The nice thing about this is that you don't have to change the data source itself which is good if it's auto-generated and you don't have control over it. You can also ignore/map fields only in certain entrytypes. See the 0.9.4 biber manual, section 2.1.1.
EDIT: The config file format will change in Biber 0.9.8 because the current format is too restrictive. Mapping will be less confusing. Here is the same solution in the new format:
<config>
<sourcemap>
<maps datatype="bibtex" map_overwrite="1">
<map>
<map_step map_field_set="ABSTRACT" map_null="1"/>
</map>
</maps>
</sourcemap>
</config>
With recent versions of biblatex and Biber you can put
\DeclareSourcemap{
\maps[datatype=bibtex]{
\map{
\step[fieldset=abstract, null]
}
}
}
into your preamble to obtain the same result.
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Best Answer
The table you show is relative to the symbols provided by
mathabx. One can saybut this will change many symbols and not always in a desirable way.
For negated relations one can first try preceding the command by
\not:The placement of the diagonal bar is not always ideal, which is why the negation of
\inhas its own command\notin. In the case of\not\approxthere is no problem.Here's a visual comparison: above the normal rendition of the symbol, using Computer Modern Math Symbols, below the
mathabxrendition. A difference in shape is evident.