In world systems theory, nations are split into core, semi-periphery, and periphery countries on the basis of their wealth, military strength, and government institutions. Core countries are those well-developed, wealthy nations that control many resources, have powerful militaries, and have strong state institutions. Periphery countries are dependent on core countries for capital and lack a strong centralized government. An undeveloped nation, or developing nation, is generally defined as a country with a less-developed industrial base and a lower standard of living.