Reality Sets

Discussion in 'Physics & Math' started by Spellbound, Mar 18, 2015.

  1. Spellbound Banned Valued Senior Member

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    Elements

    Every n-cube of n > 0 is composed of elements, or n-cubes of a lower dimension, on the (n-1)-dimensional surface on the parent hypercube. A side is any element of (n-1) dimension of the parent hypercube. A hypercube of dimension n has 2n sides (a 1-dimensional line has 2 end points; a 2-dimensional square has 4 sides or edges; a 3-dimensional cube has 6 2-dimensional faces; a 4-dimensional tesseract has 8 cells). The number of vertices (points) of a hypercube is

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    (a cube has

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    vertices, for instance).
    A simple formula to calculate the number of "n-2"-faces in an n-dimensional hypercube is:

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    The number of m-dimensional hypercubes (just referred to as m-cube from here on) on the boundary of an n-cube is

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    , where

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    and n! denotes the
    factorial of n.
    For example, the boundary of a 4-cube (n=4) contains 8 cubes (3-cubes), 24 squares (2-cubes), 32 lines (1-cubes) and 16 vertices (0-cubes).
    This identity can be proved by combinatorial arguments; each of the

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    vertices defines a vertex in a

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    -dimensional boundary. There are

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    ways of choosing which lines ("sides") that defines the subspace that the boundary is in. But, each side is counted

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    times since it has that many vertices, we need to divide with this number.
    This identity can also be used to generate the formula for the n-dimensional cube surface area. The surface area of a hypercube is:

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    .
    These numbers can also be generated by the linear
    recurrence relation

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    , with

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    , and undefined elements (where

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    = 12 lines in total.


    References:

    http://en.wikipedia.org/wiki/Cartesian_product

    http://en.wikipedia.org/wiki/Hypercube

    Because reality is composed of n-dimensional hypercubes, and the number of m-dimensional elements on the boundary of an n-dimensional hypercube is given by the equation

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    , we can represent the elements using set-builder notation

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    Where the product of A and B is the set of all ordered pairs {a,b} and the construction of the elements of the n-dimensional hypercube is given by the Minkowski sum of d mutually perpendicular line segments in each of space's dimensions. Where A and B are the sets of these elements and the Cartesian product represents the Minkowski sum.
     
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  3. Daecon Kiwi fruit Valued Senior Member

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    So... a 3d cube contains six 2d cubes (faces), twelve 1d cubes (edges) and eight 0d cubes (corners)?
     
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  5. Spellbound Banned Valued Senior Member

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    Yes.
     
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  7. Daecon Kiwi fruit Valued Senior Member

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    What about spheres?
     
  8. origin Heading towards oblivion Valued Senior Member

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    I think you're unreal...

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  9. James R Just this guy, you know? Staff Member

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    Spellbound:

    Did you have a question or a point of discussion, perhaps?
     
  10. Spellbound Banned Valued Senior Member

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    Yes. I would love to explore how set-builder notation can be used to describe hypercubes within reality.
     
  11. Spellbound Banned Valued Senior Member

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    Line segment

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    Square

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    Cube

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    4-cube (tesseract)

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    5-cube (penteract)

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    6-cube (hexeract)

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    7-cube (hepteract)

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    8-cube (octeract)

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    9-cube (enneract)

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    10-cube (dekeract)

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    11-cube (hendekeract)

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    12-cube (dodekeract)


    http://en.wikipedia.org/wiki/Hypercube
     
  12. Daecon Kiwi fruit Valued Senior Member

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    How is the hexagon a cube?
     
  13. origin Heading towards oblivion Valued Senior Member

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    That implies that there is a way to describes hypercubes outside of reality.
     
  14. Spellbound Banned Valued Senior Member

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    I was talking about sets within reality. The mathematical equation above gives the number of m-dimensional hypercubes on the boundary of its parent n-dimensional hypercube. There is obviously more than one dimension in space, so why can't there be a maximum possible number of dimensions of space in reality since we can draw it on paper? The perpendicular lines of the m-dimensional or lower dimensional hypercubes are subsets.
     
  15. origin Heading towards oblivion Valued Senior Member

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    Thanks for clearing up that you were not talking about sets outside of reality.
     
  16. RJBeery Natural Philosopher Valued Senior Member

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    I'm not sure what the point of this thread is, but I haven't seen this recurrence relation in terms of relating n-cubes and their sub-cubes before. It's very interesting, thank-you! Also, this looks similar to a partition function I came up with about 15 years ago, makes me want to go dig it up...
     

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