Zero other (english) publications by the author in the Cornell archive and only four references within. Not an indicator as to whether the paper is correct (I haven't read it), but that's "smelly".
Not really. There are many great researchers publishing in their language only. Especially in countries where research is not heavily funded. For some, 800EUR for a conference is just too much.
Yeah, and, seriously, a Russian?! Please...
Why not a Russian? For example the Russian Mathematics Olympiad is considered harder than the International Math Olympiad by many of the top contestants.