On Tue, 20 May 2014, Joseph Wright wrote: [...] > In contrast, Unicode math defines a number of alphabets in a single Unicode > font, including mathematical italic and bold mathematical italic and many > more variations. In OpenType maths fonts to date, these symbols are all > designed as single-letter identifiers and not to be used for strings of > characters such as "Re" in italic or "Set" in bold. To be clear, the Unicode position is that e.g. bold-B for magnetic field should not come from the 'bold' font but from the bold-symbols part of a single maths font: correct? That being the case, have the Unicode people considered at all multi-letter identifiers or has this simply been missed at present? (Anyone on the list sufficiently well-informed about this?) having been the stix representative to the unicode technical committe, i hope that i'm sufficiently well-informed. the unicode people didn't consider multi-letter identifiers specifically, since only single letters are (normally) given character status. as pointed out (i think by david), one goal of the alphanumeric block in plane 1 was to be able to drop single characters into text and have them recognized as math identifiers (one of the "math subgroup" was murray sargent of microsoft, who has been responsible for the ms work adding math to office). another explicit goal was to be able to search for individual math expressions by unicode to find in what documents a particular identifier had been used. explicitly *un*intended was the ability to easily use, say, fraktur or script for wedding invitations, hence the location in plane 1. the unicode goal is to have only one code per "meaning". hence the absence of the "usual version" of an alphabet (usually upright lightface) from the plane 1 math block. (the absence of lightface sans greek is an oversight; this has been resubmitted, with a reference to nist special publication 811, http://physics.nist.gov/cuu/pdf/sp811.pdf page 22, where lightface sans is used, though not by name, in the definition of the *dimensions* of si base quantities. one greek letter, theta, is shown; not sure whether the theta is upper- or lowercase, but it's the principle that's important to the utc.) more information (and history regarding the deciding example that resulted in the inclusion of the plane 1 alphanumeric block) is given in unicode tech report #25: http://www.unicode.org/reports/tr25/ regarding identifiers, see utr#25, in particular sections 2.16 and 4.4. (the latter section does strongly hint that the characters in the plane 1 block can be used for multi-letter identifiers.) hope this is helpful. -- bb