de Sitter space
A mathematical model of the universe in general relativity, characterized by a positive cosmological constant. Used in cosmology and theoretical physics.
De Sitter space is one of the vacuum solutions to Einstein's field equations with a positive cosmological constant.
Standard spelling with interpunct; the most common written form in physics literature.
Variant without interpunct, also seen in technical contexts.
From the name of Dutch astronomer Willem de Sitter (1872–1934), who first described this cosmological model.