It was for relatively short period of a few years, and many of related work at that time was done just as applied math, like Pontryagin principle developed at t

It was for relatively short period of a few years, and many of related work at that time was done just as applied math, like Pontryagin principle developed at the time. The country needed its missiles and planes after all - similarly to why the "Jewish Physics" mentioned by another commenter was allowed.