What is the economic relationship between people?

Case 1: In the ancient Greek period, a slave owner took all the fruits of a year's labor from his slaves and took his adult daughter away to work as a servant, and the slaves did not show any resistance despite their discontent. A slave is a commodity, and in this slaveholding society, the relationship between slave and slaveholder is one of subordination. The slave owner owns the freedom and totality of the slave. The relationship between the slave owner and the slave is an economic relationship between the master and the animal. Case 2: In ancient China, Emperor Tang Taizong Li Shimin wanted a painting or calligraphy treasured by one of his ministers. When the minister found out about it, he offered it to the emperor even though he was reluctant to do so. In a class society, the highest level of the imperial power asks his subordinates for paintings and calligraphy, and his subordinates have to offer the paintings to their superiors even though they are unwilling to do so, which is a kind of unequal economic relationship. Case 3: The day before yesterday, at a market in Shantou City, Citizen A and Citizen B exchanged labor products they needed with each other through bargaining. In the modern economic society, people are in an equal relationship with each other. Their transactions have to be carried out willingly.　A fair and reasonable situation completes a reciprocal transaction. This is the modern equal economic relationship between man and man.