I'll admit to not knowing my history well at this point, but wasn't mathematics and the sciences rather important to socialist countries? Now I don't doubt that ideology will have been injected in certain instances, but at least in mathematics and physics that's a bit harder to do and hence there were quite a number of accomplished mathematicians in the USSR.

Even beyond the natural sciences, this seems to have been somewhat the case. I remember my uncle, who is as unabashedly anti-communist as it gets, once showing me a grammar of some minority language written in the GDR and commenting, almost with admiration, that "back then, they invested a lot of resources on things like that".

Yes, the Soviet Union was actually quite enlightened on the science front, and they were especially good in teaching Mathematics and elevating talent. Just compare a soviet era math textbook to its “western” counterpart, the former is much more in-depth. Also, they were famously anti-religion, putting science above it.