Pauling's principle of electroneutrality states that each atom in a stable substance has a charge close to zero.
 It was formulated by Linus Pauling in 1948 and later revised.
 The principle has been used to predict which of a set of molecular resonance structures would be the most significant, to explain the stability of inorganic complexes and to explain the existence of π-bonding in compounds and polyatomic anions containing silicon, phosphorus or sulfur bonded to oxygen; it is still invoked in the context of coordination complexes.
 However, modern computational techniques indicate many stable compounds have a greater charge distribution than the principle predicts (they contain bonds with greater ionic character).
The postcautionary principle is a principle of "de facto" environmental management formulated by John Paull in 2007.
 It is suggested that the postcautionary principle, as the antithesis of the precautionary principle, has guided environmental management, as it is actually practised.
The country of origin principle is a principle in the law of the European Union for resolving conflict of laws between Member States.
 The principle states that, where an action or service is performed in one country but received in another, the applicable law is the law of the country where the action or service is performed.
 The opposing principle is the "country of reception principle".
 For example, if a sale of goods is made over the Internet from a website in France to a purchaser in Italy, the country of origin principle would be said to apply if French law applied to the transaction, and the country of reception principle if Italian law prevailed.
In Forensic science, Locard's exchange principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence.
 Dr. Edmond Locard (13 December 1877 – 4 May 1966) was a pioneer in forensic science who became known as the Sherlock Holmes of France.
 He formulated the basic principle of forensic science as: "Every contact leaves a trace".
 Paul L. Kirk expressed the principle as follows:
In U.S. law, the bad tendency principle is a test which permits restriction of freedom of speech by government if it is believed that a form of speech has a sole tendency to incite or cause illegal activity.
 The principle, formulated in "Patterson v. Colorado", (1907) was seemingly overturned with the "clear and present danger" principle used in the landmark case "Schenck v. United States" (1919), as stated by Justice Oliver Wendell Holmes, Jr. Yet eight months later, at the start of the next Term in "Abrams v. United States" (1919) the Court again used the bad tendency test to uphold the conviction of a Russian immigrant who published and distributed leaflets calling for a general strike and otherwise advocated revolutionary, anarchist, and socialist views.
 Holmes dissented in "Abrams", explaining how the "clear and present danger test" should be employed to overturn Abrams' conviction.
 The arrival of the "bad tendency" test resulted in a string of politically incorrect rulings such as Whitney v. California (1927), where a woman was convicted simply because of her association with the Communist Party.
 The court ruled unanimously that although she had not committed any crimes, her relationship with the Communists represented a "bad tendency" and thus was unprotected.
 The "bad tendency" test was finally overturned in Brandenburg v. Ohio (1969) and was replaced by the "imminent lawless action" test.
Separation of the elements is an aesthetic principle formulated by the German modernist theatre practitioner Bertolt Brecht.
 The principle bears primarily on the theatrical register, though it has implications for the dramatic and performative as well.
 The principle of the "separation of the elements" stands in diametric opposition to that of the "integrated work of art" proposed by Wagner.
The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.
 In the case of electrons in atoms, it can be stated as follows: it is impossible for two electrons of a poly-electron atom to have the same values of the four quantum numbers: "n", the principal quantum number, "ℓ ", the angular momentum quantum number, "m", the magnetic quantum number, and "m", the spin quantum number.
 For example, if two electrons reside in the same orbital, and if their "n", "ℓ ", and "m" values are the same, then their "m" must be different, and thus the electrons must have opposite half-integer spins of 1/2 and −1/2.
 This principle was formulated by Austrian physicist Wolfgang Pauli in 1925 for electrons, and later extended to all fermions with his spin-statistics theorem of 1940.
"One country, two systems" is a constitutional principle formulated by Deng Xiaoping, the Paramount Leader of the People's Republic of China (PRC), for the reunification of China during the early 1980s.
 He suggested that there would be only one China, but distinct Chinese regions such as Hong Kong and Macau could retain their own capitalist economic and political systems, while the rest of China uses the socialist system.
 Under the principle, each of the two regions could continue to have its own political system, legal, economic and financial affairs, including external relations with foreign countries.
The totality principle is a common law principle which applies when a court imposes multiple sentences of imprisonment.
 The principle was first formulated by David Thomas in his 1970 study of the sentencing decisions of the Court of Appeal of England and Wales:
Tensions between people from Hong Kong and mainland China have developed since the handover of Hong Kong's sovereignty to China in 1997, and in particular since the late 2000s and early 2010s.
 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.
 Increasingly, these tensions have resulted in a rising sentiment in Hong Kong of hostility to "mainlanders" and resentment at a perceived trend towards assimilation and interference from the mainland and the central government, and at the same time a rising sentiment in mainland China of bewilderment and resentment at assertions that Hong Kong is, and should remain, different from the mainland in terms of political system, culture and language.

Question: Who formulated the principle that involves the country that is hostile to "mainlanders"?
Answer: Deng Xiaoping