Displaying mathematical symbols with the apropriate font

[Kaloian Doganov]

Hello,

I would like to use mathematical symbols in an Emacs text buffer -- for
example: 𝑛 U+1D45B.  Unfortunately this symbol (an all others in the
same Unicode block) is displayed in Emacs as a Chineese ideograph,
although the file written on disk is perfectly encoded in UTF-8 and the
character in question is successfuly interpreted as U+1D45B in other
programs.  So, I guess, this is just a display-related problem in Emacs.

C-u C-x = on the character shows:

/------------------------------------------------
        character: 𝑛 (119899, #o352133, #x1d45b)
preferred charset: unicode (Unicode (ISO10646))
       code point: 0x1D45B
           syntax: w    which means: word
      buffer code: #xF0 #x9D #x91 #x9B
        file code: #xF0 #x9D #x91 #x9B (encoded by coding system utf-8-emacs)
          display: by this font (glyph code)
    x:-arphic-ar pl ukai cn-book-r-normal--16-116-100-100-p-160-gb18030.2000-0 
(#x1D45B)

Character code properties: customize what to show
  name: MATHEMATICAL ITALIC SMALL N
  general-category: Ll (Letter, Lowercase)
  canonical-combining-class: 0 (Spacing, split, enclosing, reordrant, and 
Tibetan subjoined)
  bidi-class: L (Left-to-Right)
  decomposition: (<font> 110) (<font> 'n')
  mirrored: N

There are text properties here:
  auto-composed        t
  fontified            t
  rear-nonsticky       t
\------------------------------------------------

It looks like for some reason Emacs does not use a suitable font for
this character.  Then I've tried to augment the current fontset with a
range:

(set-fontset-font (query-fontset (frame-parameter nil 'font))
                  (cons (decode-char 'ucs #x1d400)
                        (decode-char 'ucs #x1d7ff))
                  '("dejavu sans" . "iso10646-1"))

But this does not have any visible effects.  C-u C-x = still shows the
same font as cited above.  What should I do to display this character
properly?

I am using GNU Emacs 23.0.60.1 (i486-pc-linux-gnu, GTK+ Version 2.12.9)
of 2008-07-16 on tzotzolana, modified for gNewSense.