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In mathematics, especially in the area of mathematical analysis known as dynamical systems theory, a linear flow on the torus is a flow on the ''n''-dimensional torus : which is represented by the following differential equations with respect to the standard angular coordinates (θ1, θ2, ..., θ''n''): : The solution of these equations can explicitly be expressed as : If we respesent the torus as R''n''/Z''n'' we see that a starting point is moved by the flow in the direction ω=(ω1, ω2, ..., ω''n'') at constant speed and when it reaches the border of the unitary ''n''-cube it jumps to the opposite face of the cube. For a linear flow on the torus either all orbits are periodic or all orbits are dense on a subset of the ''n''-torus which is a ''k''-torus. When the components of ω are rationally independent all the orbits are dense on the whole space. This can be easily seen in the two dimensional case: if the two components of ω are rationally independent then the Poincaré section of the flow on an edge of the unit square is an irrational rotation on a circle and therefore its orbits are dense on the circle, as a consequence the orbits of the flow must be dense on the torus. ==See also== *Completely integrable system *Ergodic theory *Quasiperiodic motion 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Linear flow on the torus」の詳細全文を読む スポンサード リンク
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