With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Thanos appears in Guardians of the Galazy.
text_B: Half-space may refer to  :. Half-space -LRB- geometry -RRB- , either of the two parts into which a plane divides Euclidean space. Half-space -LRB- punctuation -RRB- , a spacing character half the width of a regular space. -LRB- Poincare -RRB- Half-space model , a model of 3-dimensional hyperbolic geometry or higher-dimensional hyperbolic geometry using a Euclidean half-space. Half-space model. Half-space model. 3-dimensional. 3-dimensional. hyperbolic geometry. hyperbolic geometry. Half-space model -LRB- oceanography -RRB- , an estimate for seabed height in areas without significant subduction. Half-space model. Half-space model. Siegel upper half-space , a set of complex matrices with positive definite imaginary part. Siegel upper half-space. Siegel upper half-space
not_related.