Deutsch: Im linken Teilbild ist die Addition durch Translation gegeben, wobei man, wenn man über eine Klebekannte geht bei der entsprechenden anderen Klebekante wieder rauskommt.
Im rechten Teilbild ist die Addition durch Rotation um die beiden eingezeichenten Kreise gegeben. DIe grünen Punkte markieren die Elemente des Vektorraums.
English: On the left, addition is given by translation. If one moves over a gluing edge, one comes out at the corresponding other gluing edge and continues the movement.
On the right, addition is given by rotation around the two circles drawn on the torus. The green dots represent the elements of the vector space.
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