Re: Motion P1788/M0034.01 Notation:NO
On 2012-06-06 02:49:34 -0600, Alan Eliasen wrote:
> We must ensure, however, that we adopt a standard that *can* work
> with a global, worldwide standard for text which is Unicode, and, for
> correctness and our sanity, it should be likely to survive
> cut-and-paste, and needs to be communicable in emails, programming
> languages, and other modern constructs that support Unicode. Even if
> you can manage, with more research, to compose a Unicode ℝ character
> with overline, such as by the sequence U+211D U+0305, to make ℝ̅, it is
> questionable if it will survive cutting-and-pasting, or even if its
> display will be visible and distinguishable.
No problems on my side, except that it is not very visible due to the
small font I use. In any case, the context should help. Copy-paste
works too.
> I would prefer the conventions used in the literature (e.g. Hansen,
> Walster) of using ℝ* to indicate the extended reals, for example.
I strongly disagree. First, ℝ* for the extended reals is not
"the convention". In France, I've always seen ℝ* to mean ℝ\{0}.
And before conventions (which are often local), international
standards must be followed. And ℝ* seems to have the standard
meaning of ℝ\{0}:
http://en.wikipedia.org/wiki/ISO_31-11
> Overlines are also too overloaded with meanings: negation of a term
> in set theory, vectors, complex conjugates, etc.
overloaded just like *.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)