ANSI - INCITS/ISO/IEC TR 9573-13
Information technology - SGML support facilities - Techniques for using SGML - Part 13: Public entity sets for mathematics and science (TECHNICAL REPORT)
|Publication Date:||1 January 1991|
Tens of thousands of graphic characters are used in the publishing of text, of which relatively few have been incorporated into standard coded character sets. Even where standard coded representations exist, however, there may be situations in which they cannot be keyboarded conveniently, or in which it is not possible to display the desired visual depiction of the characters.
To help overcome these barriers to successful interchange of SGML documents, this part of ISO/IEC TR 9573 defines character entity sets for some of the widely used special graphic characters. The entity repertoires are based on applicable published and proposed International Standards for coded character sets, and current industry and professional society practice.
NOTE 1 Entity repertoires are necessarily larger and more repetitious than character sets, as they deal in general with higher-level constructs. For example, unique entities have been defined for each accented Latin alphabetic character, while a character set might represent such characters as combinations of letters and diacritical mark characters. These public entity sets should therefore not be construed as requirements for new standard coded character sets.
In many instances upper- and lower-case is used to differentiate the names of different entities. It is thus assumed that a concrete syntax where entity names are case sensitive is used.
NOTE 2 In the reference concrete syntax, the entity names are case sensitive.