Point systems
Overview
Important
A point system is a finite set of points in the plane or in space. We often study their arrangement, such as whether some points are collinear (on the same line), or how many segments or shapes can be formed by connecting them.
Important properties
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The number of points in the system (cardinality).
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Whether any three points are collinear (no three collinear is a common condition).
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How many segments can be formed by connecting pairs of points.
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Special arrangements, such as points on a circle or in a grid.