How many LaTeX characters have Unicode equivalents, and which characters and mathematical character combinations cannot be represented by Unicode?

Question

I would like to know how many LaTeX characters, including all the special math symbols, can be represented by Unicode. Would I be right to say, that nowadyas, LaTeX's strangths over Unicode are mainly its ability to draw diagrams, which cannot be created with Unicode alone?

Also, if for example I need to typeset something like "integral from a to b" with subscripts and suprescripts, or even "e to the power of (x to the power of y)", then can I do this with Unicode or do I just need LaTeX in order to generate the smaller superscripts and subscripts?

Also, to what extent can I combine LaTeX with Unicode math characters and would the typesetting be the same if I use LaTeX notation to generate math characters rather than Unicode characters serving the same purpose?

Thanks.

Answer 1

partial, and probably unsatisfactory, answer.

unicode alone can't do everything. for example, if you want an integral from x=1 to \infty, unicode has the codes, but it isn't by itself able to position sub/superscripts or limits. so at a minimum, some sort of markup and composition facility is required.

markup could as well be mathml as latex, but that's up to whoever is preparing the document.

as for whether "all" latex characters/symbols are covered by unicode, the effort made for the benefit of stipub (see http://www.ams.org/STIX for the history of the stix project) attempted to get as many such symbols as possible accepted into unicode. if a symbol was requested by one of the stipub organizations, then it went onto the list, and by and large the unicode technical committee received that request as an acceptable level of documentation. for some edge cases (some symbols in the stmaryrd collection or in tipa, for example) which were not on the main stipub lists, additional documentation -- in the form of articles or books published by recognized technical publishers -- was required, and in its absence, no action was taken. (if someone can provide a suitable citation for any "missing" symbol, the effort to add new symbols is ongoing.)

what did happen is that the unicode technical committee accepted the proposition that math notation is effectively a "language", and as such, symbols in common use should be encoded just as letters for "minor" human languages, alive or dead, are encoded. this is what is required for mathematicians and other scientists to communicate on the web.

i am not aware that a complete list of symbols, with their visual representation and associated unicode (and, potentially, a "tex name") exists yet. i hope that this information can be added to the "comprehensive symbols list" (texdoc comprehensive), but that is a massive undertaking (in which i am willing to participate, but haven't yet contacted the author to that effect). and some glitches in the stix fonts, which were the outcome of the stix project, remain to be ironed out, in particular the location of quite a few "unicodes" in the private use area.

regarding direct use of unicodes or the "native" symbols vs. "tex names", ability to do so depends on the engine in use. it's probably not possible with pdflatex, but should be relatively straightforward with xelatex provided suitable fonts are available.

Answer 2

Many of the applications I write have some connection to LaTeX. Either they create files that LaTeX inputs or they parse LaTeX code, so I've had to produce some mappings between Unicode and LaTeX commands.

flowframtk is a graphical application that can export to .tex (or .sty or .cls) and Unicode characters entered into the graphical environment can be mapped to LaTeX commands. If you install flowframtk, run the application and then quit it, you should find a directory containing the application settings (~/.flowframtk/ on Unix-like systems or flowframtk-settings on Windows). This directory should include (amongst other files) the text-mode (textmappings.prop) and math-mode (mathmappings.prop) mappings. The files are tab-separated with three columns. The first has the Unicode code point, the second the closest LaTeX equivalent and the third the package(s) required. The files are too large to reproduce here. (The text mode mappings has 200 lines and the math mode mappings has 795 lines.)

The texparser library is designed to parse LaTeX files, but also contains mappings from LaTeX to Unicode, although these are contained within the Java source code.