Half-space may refer to:
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Half-space (geometry)
In geometry, a half-space is either of the two parts into which a plane divides the three-dimensional Euclidean space.
If the space is two-dimensional, then a half-space is called a half-plane (open or closed). A half-space in a one-dimensional sp ...
, either of the two parts into which a plane divides Euclidean space
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Half-space (punctuation), a spacing character half the width of a regular space
* (Poincaré)
Half-space model, a model of 3-dimensional hyperbolic geometry or higher-dimensional hyperbolic geometry using a Euclidean half-space
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Half-space model (oceanography), an estimate for seabed height in areas without significant subduction
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Siegel upper half-space
In mathematics, the Siegel upper half-space of degree ''g'' (or genus ''g'') (also called the Siegel upper half-plane) is the set of ''g'' × ''g'' symmetric matrices over the complex numbers whose imaginary part is positive definite. It ...
, a set of complex matrices with positive definite imaginary part
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