People can be divided in different group by their races, history, language, region and interest. Like mathematical elements，these group can be inclusive and exclusive. However, people can be conflict under upper layer.
A typical example is about Mainland China and Taiwan. People in these two regions look very similar from inside to outside. However, they also have a lot of conflict. They are defiantly belongs to Asian race. From the history aspect, they share the same ancestor. They both claim that they heritage of Chinese culture. They have exactly same eating habitat and festival. More important, Mainland China and Taiwan used to belong to a same country without a doubt. At this time, the conflict between them has raise up. For some political reason, people from Mainland China and Taiwan gradually goes apart. They became antithesis. Different political system is the key of conflict. Some people of Taiwanese want to be a independent country.
Many people mention the conflict in different races in the same country. I want to make a supplement of conflict occurs in same races from different region—it is know as Geographical discrimination. China has 34 provinces with huge gap in economy development and difference in life style. Difference born conflict. The common impression of shanghai people is rich, picky and xenophobic. The common misunderstanding of people in Henan province is cunning and cheater.