- The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, Congo-Zaire, or simply either Congo or the Congo, is a country in Central Africa. By land area, the DRC is the second-largest country in Africa and the 11th-largest in the world. With a population of around 105 million, the Democratic Republic of the Congo is the most populous Francophone country in the world. The national capital and largest city is Kinshasa, which is also the economic center. The country is bordered by the Republic of the Congo, Central African Republic, South Sudan, Uganda, Rwanda, Burundi, Tanzania (across Lake Tanganyika), Zambia, Angola, the Cabinda exclave of Angola, and the South Atlantic Ocean.
- On the dimensionality of spacetime (space.mit.edu)
Some superstring theories have more than one effective low-energy limit corresponding to classical spacetimes with different dimensionalities. We argue that all but the (3 + 1)-dimensional one might correspond to ‘dead worlds’, devoid of observers, in which case all such ensemble theories would actually predict that we should find ourselves inhabiting a (3 + 1)-dimensional spacetime. With more or less than one time dimension, the partial differential equations of nature would lack the hyperbolicity property that enables observers to make predictions. In a space with more than three dimensions, there can be no traditional atoms and perhaps no stable structures. A space with less than three dimensions allows no gravitational force and may be too simple and barren to contain observers.
