Wallerstein, Core/Periphery, Semi-Periphery

Wallerstein spoke about the term, core/periphery, and semi-periphery. He defined them as, "Core/Periphery- Defines the difference between developed countries and developing countries, characterized e.g. by power or wealth. The core stands refers to developed countries, and the periphery is a synonym for the dependent developing countries. The main reason for the position of the developed countries is economic power.
Semi-periphery- Defines states that are located between core and periphery, they benefit from the periphery and have to contribute to the centre. Mostly these states are authoritarian, allowing the core to put oppressive measures on them" (Wikipedia).

Its a concept that seems difficult to understand, but it is not if one looks into its definition. The relation between core and the periphery is desribed as dependent and the exploitation between rich and poor. Semi-periphery which some look at at being problematic say its a "vague allusion to a middle ground between core and periphery. To understand Wallerstein's ideas one would need to analyze his ideas more than just from outside the source. "Wallerstein does not conceive of these differences as mere residues or irregularities that can and will be overcome as the system as a whole evolves. Much more, a lasting division of the world in core, semi-periphery and periphery is an inherent feature of the world-system" (Modern World System 1).

These ideas by Wallerstein can still be observed today in sociology. Wallerstein was born in 1930 and he has in fact still has been giving speeches about his ideas and theories. The Modern World System is probably the most popular thing from Wallerstein, but his work is still discussed today.