Twas actually the Russians who developed the equations for stealth.
Just the US went and developed it and the materials.
The theory has been out there for ages, the chinese have enough smart people to look at the many pictures of the F-22 to work it out.
It all comes down to materials and electronics of which I'd say the Russians and the Chinese aren't that far behind. You can mump and moan all you want about the F-117 shootdown but I wouldn't be surprised if they were already working on it.
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