Help using DeclareUnicodeCharacter for russian

[ludvig-faddeev]

> Sent: Friday, June 11, 2021 at 5:04 PM
> From: "Gavin Smith" <gavinsmith0123@gmail.com>
> To: ludvig-faddeev@gmx.com
> Cc: "help-texinfo gnu" <help-texinfo@gnu.org>
> Subject: Re: Help using DeclareUnicodeCharacter for russian
>
> On Thu, Jun 10, 2021 at 11:53 PM <ludvig-faddeev@gmx.com> wrote:
> >
> > I am trying to declare unicode characters for russian
> >
> > @macro ru
> >
> > \DeclareUnicodeCharacter{1040}{\ensuremath\rua}
> > \DeclareUnicodeCharacter{1041}{\ensuremath\rube}
> > \DeclareUnicodeCharacter{1042}{\ensuremath\ruve}
> > \DeclareUnicodeCharacter{1043}{\ensuremath\rughe}
> > \DeclareUnicodeCharacter{1044}{\ensuremath\rude}
> > \DeclareUnicodeCharacter{1045}{\ensuremath\ruie}
> > \DeclareUnicodeCharacter{1046}{\ensuremath\ruzhe}
> > \DeclareUnicodeCharacter{1047}{\ensuremath\ruze}
> >
> > @end macro
> >
> 
> As well as using @tex instead of @macro as Jacob said, where are you
> getting the names \rua, \rube, \ruve from?

You may have found a mistake as I thought I could declare \rua as tex command
for the corresponding unicode character.
 
> You would also have to make sure a Cyrillic font was loaded and access
> the glyphs in that font. Look at the definition of \euro in
> texinfo.tex for how a font can be loaded on demand.
> 
> I don't foresee a problem with adding this to texinfo.tex as it would
> probably be only slightly more complicated than the Greek alphabet.
> 
> I expect that the document I sent earlier was written in the KOI-8
> encoding (an 8-bit encoding) rather than Unicode.
> 
> I'm curious what the use of this is: do you speak Russian? Do Russian
> mathematicians use Cyrillic letters for variables?
> 

Almost everything is written with Latin and Greek letters.  And
we keep with "sin" for the sine function, "lim" for limit, "ker"
for kernel, and "Gal" for Galois group.

Another cyrillic letter in international use is Л for the
Lobachevsky function in hyperbolic geometry.

I gave a lecture in Russia last year where I discussed Belyi
polynomials using Б(t), since Б is the first letter of Belyi's
name in Russian.  But please note that I wasn't just picking some
random letter like Ж or Ю for the sake of using "exotic" letters
without reason.