a small update on unicode and math symbols;

roozbeh says

There are also ones that will most probably never get into Unicode, like
the dotless j.

[...]

Unicode recommends modifiers for the unified math symbols, which will
become something like \mathmakelonger{\rightarrow} internally.

this is still an active area.  there has been a strong counterproposal
to explicitly encode the long arrows, based on the fact that they are
given distinct entity names in the sgml public entity set isoamsa,
and the concept of "disunification" has some strong support.  the
defining proposal will be distributed in a week or two to the utc
for a letter ballot; i can't predict whether it will or won't be
accepted, but i can say with assurance that the matter isn't yet
settled, and if the decision ends up to use a modifier, it won't
be a *unicode* modifier, but one defined in mathml.
-- bb