Genus (InstanceTopic, 3)

From Hi.gher. Space

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[[Line (object)|Lines]] always have a genus of zero. If a hole was created it would be split in half.
[[Line (object)|Lines]] always have a genus of zero. If a hole was created it would be split in half.
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There are two types of holes that a shape can have. ''Pockets'' are holes completely inside the object and cannot be seen by any outside viewer (unless the being viewing the shape is in a higher dimension than the shape itself). Ordinary ''holes'' are ones that can be seen from the outside, for example the hole in a [[torus]]. The only type of hole that can be placed inside a [[polygon]] is a pocket, as creating a normal hole would split the shape in half.
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There are two{{hmm}} types of holes that a shape can have. ''Pockets'' are holes completely inside the object and cannot be seen by any outside viewer (unless the being viewing the shape is in a higher dimension than the shape itself). Ordinary ''holes'' are ones that can be seen from the outside, for example the hole in a [[torus]]. The only type of hole that can be placed inside a [[polygon]] is a pocket, as creating a normal hole would split the shape in half.
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It is actually debatable that there may be ''n''-1 possible types of holes in any given ''n''-dimensional shape.
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[[Category:Geometrical properties]]
[[Category:Geometrical properties]]

Revision as of 22:16, 15 June 2007

The genus of a shape is equal to how many "holes" it has that fully pierce the shape.

Lines always have a genus of zero. If a hole was created it would be split in half.

There are two(?) types of holes that a shape can have. Pockets are holes completely inside the object and cannot be seen by any outside viewer (unless the being viewing the shape is in a higher dimension than the shape itself). Ordinary holes are ones that can be seen from the outside, for example the hole in a torus. The only type of hole that can be placed inside a polygon is a pocket, as creating a normal hole would split the shape in half.