Question: Who formulated the principle that involves the country that is hostile to "mainlanders"?
Sentence (from "Hong Kong–Mainland China conflict"): Various factors have contributed to the development of such tensions: these include a difference between the popular interpretation in Hong Kong of the "One country, two systems" constitutional principle as against the Chinese government's official interpretation; policies of the Hong Kong and central governments to encourage mainland visitors to Hong Kong; and changing economic environments in Hong Kong and mainland China.
Relevant evidence: No