Half-space

Half-space may refer to:

• Half-space (geometry), either of the two parts into which a plane divides Euclidean space
  • (Poincaré) Half-space model, a model of hyperbolic geometry using a Euclidean half-space
  • Siegel upper half-space, a set of complex matrices with positive definite imaginary part
• Half-space (punctuation), a spacing character half the width of a regular space
• Half-space model (oceanography), an estimate for seabed height in areas without significant subduction