+@node Embedded LaTeX, Exporting, Agenda views, Top
+@chapter Embedded LaTeX
+@cindex @TeX{} interpretation
+@cindex La@TeX{} interpretation
+
+Plain ASCII is normally sufficient for almost all note taking. One
+exception, however, are scientific notes which need to be able to
+contain mathematical symbols and the occasional formula.
+La@TeX{}@footnote{La@TeX{} is a macro system based on Donald E. Knuth's
+@TeX{} system. Many of the features described here as ``La@TeX{}'' are
+really from @TeX{}, but for simplicity I am blurring this distinction.}
+is widely used to typeset scientific documents. Org-mode supports
+embedding La@TeX{} code into its files, because many academics are used
+to read La@TeX{} source code, and because it can be readily processed
+into images for HTML production.
+
+It is not necessary to mark La@TeX{} macros and code in any special way.
+If you observe a few conventions, Org-mode knows how to find it and what
+to do with it.
+
+@menu
+* Math symbols:: TeX macros for symbols and Greek letters
+* Subscripts and Superscripts:: Simple syntax for raising/lowering text
+* LaTeX fragments:: Complex formulas made easy
+* Processing LaTeX fragments:: Previewing LaTeX processing
+* CDLaTeX mode:: Speed up entering of formulas
+@end menu
+
+@node Math symbols, Subscripts and Superscripts, Embedded LaTeX, Embedded LaTeX
+@section Math symbols
+
+You can use La@TeX{} macros to insert special symbols like @samp{\alpha}
+to indicate the Greek letter, or @samp{\to} to indicate an arrow.
+Completion for these macros is available, just type @samp{\} and maybe a
+few letters, and press @kbd{M-@key{TAB}} to see possible completions.
+Unlike La@TeX{} code, Org-mode allows these macros to be present
+without surrounding math delimiters, for example:
+
+@example
+Angles are written as Greek letters \alpha, \beta and \gamma.
+@end example
+
+During HTML export (@pxref{HTML export}), these symbols are translated
+into the proper syntax for HTML, for the above examples this is
+@samp{α} and @samp{→}, respectively.
+
+@node Subscripts and Superscripts, LaTeX fragments, Math symbols, Embedded LaTeX
+@section Subscripts and Superscripts
+
+Just like in La@TeX{}, @samp{^} and @samp{_} are used to indicate super-
+and subscripts. Again, these can be used without embedding them in
+math-mode delimiters. To increase the readability of ASCII text, it is
+not necessary (but OK) to surround multi-character sub- and superscripts
+with curly braces. For example
+
+@example
+The mass if the sun is M_sun = 1.989 x 10^30 kg. The radius of
+the sun is R_@{sun@} = 6.96 x 10^8 m.
+@end example
+
+To avoid interpretation as raised or lowered text, you can quote
+@samp{^} and @samp{_} with a backslash: @samp{\_} and @samp{\^}.
+
+During HTML export (@pxref{HTML export}), subscript and superscripts
+are surrounded with @code{<sub>} and @code{<sup>} tags, respectively.
+
+@node LaTeX fragments, Processing LaTeX fragments, Subscripts and Superscripts, Embedded LaTeX
+@section LaTeX fragments
+
+With symbols, sub- and superscripts, HTML is pretty much at its end when
+it comes to representing mathematical formulas. More complex
+expressions need a dedicated formula processor. To this end, Org-mode
+can contain arbitrary La@TeX{} fragments. It provides commands to
+preview the typeset result of these fragments, and upon export to HTML,
+all fragments will be converted to images and inlined into the HTML
+document. For this to work you need to be on a system with a working
+La@TeX{} installation. You also need the @file{dvipng} program,
+available at @url{http://sourceforge.net/projects/dvipng/}.
+
+La@TeX{} fragments don't need any special marking at all. The following
+snippets will be identified as LaTeX source code:
+@itemize @bullet
+@item
+Environments of any kind. The only requirement is that the
+@code{\begin} statement appears on a new line, preceded by only
+whitespace.
+@item
+Text within the usual La@TeX{} math delimiters. To avoid conflicts with
+currency specifications, single @samp{$} characters are only recognized
+as math delimiters if the enclosed text contains at most two line breaks,
+is directly attached to the @samp{$} characters with no whitespace in
+between, and if the closing @samp{$} is followed by whitespace or
+punctuation. For the other delimiters, there is no such restriction, so
+when in doubt, use @samp{\(...\)} as inline math delimiters.
+@end itemize
+
+@noindent For example:
+
+@example
+\begin@{equation@} % arbitrary environments,
+x=\sqrt@{b@} % even tables, figures
+\end@{equation@} % etc
+
+If $a^2=b$ and \( b=2 \), then the solution must be
+either $$ a=+\sqrt@{2@} $$ or \[ a=-\sqrt@{2@} \].
+@end example
+
+@noindent
+If you need any of the delimiter ASCII sequences for other purposes, you
+can configure the option @code{org-format-latex-options} to deselect the
+ones you do not wish to have interpreted by the La@TeX{} converter.
+
+@node Processing LaTeX fragments, CDLaTeX mode, LaTeX fragments, Embedded LaTeX
+@section Processing LaTeX fragments
+
+La@TeX{} fragments can be processed to produce a preview images of the
+typeset expressions:
+
+@table @kbd
+@kindex C-c C-x C-l
+@item C-c C-x C-l
+Produce a preview image of the La@TeX{} fragment at point and overlay it
+over the source code. If there is no fragment at point, process all
+fragments in the current entry (between two headlines). When called
+with a prefix argument, process the entire subtree. When called with
+two prefix arguments, or when the cursor is before the first headline,
+process the entire buffer.
+@kindex C-c C-c
+@item C-c C-c
+Remove the overlay preview images.
+@end table
+
+During HTML export (@pxref{HTML export}), all La@TeX{} fragments are
+converted into images and inlined into the document if the following
+setting is active:
+
+@lisp
+(setq org-export-with-LaTeX-fragments t)
+@end lisp
+
+@node CDLaTeX mode, , Processing LaTeX fragments, Embedded LaTeX
+@section Using CDLaTeX to enter math
+
+CDLaTeX-mode is a minor mode that is normally used in combination with a
+major LaTeX mode like AUCTeX in order to speed-up insertion of
+environments and math templates. Inside Org-mode, you can make use of
+some of the features of cdlatex-mode. You need to install
+@file{cdlatex.el} and @file{texmathp.el} (the latter comes also with
+AUCTeX) from @url{http://www.astro.uva.nl/~dominik/Tools/cdlatex}.
+Don't turn cdlatex-mode itself under Org-mode, but use the light
+version @code{org-cdlatex-mode} that comes as part of Org-mode. Turn it
+on for the current buffer with @code{M-x org-cdlatex-mode}, or for all
+Org-mode files with
+
+@lisp
+(add-hook 'org-mode-hook 'turn-on-org-cdlatex)
+@end lisp
+
+When this mode is enabled, the following features are present (for more
+details see the documentation of cdlatex-mode):
+@itemize @bullet
+@kindex C-c @{
+@item
+Environment templates can be inserted with @kbd{C-c @{}.
+@item
+@kindex @key{TAB}
+The @key{TAB} key will do template expansion if the cursor is inside a
+LaTeX fragment@footnote{Org-mode has a method to test if the cursor is
+inside such a fragment, see the documentation of the function
+@code{org-inside-LaTeX-fragment-p}.}. For example, @key{TAB} will
+expand @code{fr} to @code{\frac@{@}@{@}} and position the cursor
+correctly inside the first brace. Another @key{TAB} will get you into
+the second brace. Even outside fragments, @key{TAB} will expand
+environment abbreviations at the beginning of a line. For example, if
+you write @samp{equ} at the beginning of a line and press @key{TAB},
+this abbreviation will be expanded to an @code{equation} environment.
+To get a list of all abbreviations, type @kbd{M-x cdlatex-command-help}.
+@item
+@kindex _
+@kindex ^
+Pressing @kbd{_} and @kbd{^} inside a LaTeX fragment will insert these
+characters together with a pair of braces. If you use @key{TAB} to move
+out of the braces, and if the braces surround only a single character or
+macro, they are removed again (depending on the variable
+@code{cdlatex-simplify-sub-super-scripts}).
+@item
+@kindex `
+Pressing the backquote @kbd{`} followed by a character inserts math
+macros, also outside LaTeX fragments. If you wait more than 1.5 seconds
+after the backquote, a help window will pop up.
+@item
+@kindex '
+Pressing the normal quote @kbd{'} followed by another character modifies
+the symbol before point with an accent or a font. If you wait more than
+1.5 seconds after the backquote, a help window will pop up. Character
+modification will work only inside La@TeX{} fragments, outside the quote
+is normal.
+@end itemize
+
+@node Exporting, Publishing, Embedded LaTeX, Top