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Packing problems

Contents
    Polyhedra in spheres
Related fields
Packing of irregular objects
See also
Notes
References
External links

Spheres or circles packed loosely (top) and more densely (bottom)
Covering/packing-problem pairs
Covering problems Packing problems
Minimum set cover Maximum set packing
Minimum edge cover Maximum matching
Minimum vertex cover Maximum independent set
Bin covering Bin packing
Polygon covering Rectangle packing

The problem of finding the smallest ball such that k≤n+1, and in an infinite-dimensional Hilbert space with no restrictions. It is worth describing in detail here, to give a flavor of the general problem. In this case, a configuration of (k−1) dimensional simplex with edge 2; this is easily realized starting from an orthonormal basis. A small computation shows that the distance of each vertex from the barycenter is k open unit balls centered at x1,…,xk be the centers of x0. Consider the map from the finite set xj in the corresponding 1≤i<j≤k, 1≤j≤k one has k disjoint unit open balls in a ball of radius r if and only if {ej}j is an orthonormal basis, are disjoint and included in a ball of radius r is

People determine the number of spherical objects of given diameter R that will pack R the spheres arrange to ordered structures, called columnar structures.

Polyhedra in spheres

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People determine the minimum radius dn, between points. Optimal solutions have been proven for dn, between points. To convert between these two formulations of the problem, the square side for unit circles will be n < 300.

  • Packing circles in an equilateral triangle - Optimal solutions are known for n from 1-10, 14-16, 22-25, 33-36, 62-64, 79-81, 98-100, and any square integer. The wasted space is asymptotically (L,W ) has some applications such as loading of boxes on pallets and, specifically, woodpulp stowage. For example, it is possible to pack 147 rectangles of size (137,95) in a rectangle of size (1600,1230).
  • Packing different rectangles in a rectangle: The problem of packing multiple rectangles of varying widths and heights in an enclosing rectangle of minimum area (but with no boundaries on the enclosing rectangle's width or height) has an important application in combining images into a single larger image. A web page that loads a single larger image often renders faster in the browser than the same page loading multiple small images, due to the overhead involved in requesting each image from the web server. The problem is NP-complete in general, but there are fast algorithms for solving small instances.
  • Related fields

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    In tiling or tessellation problems, there are to be no gaps, nor overlaps. Many of the puzzles of this type involve packing rectangles or polyominoes into a larger rectangle or other square-like shape.

    There are significant theorems on tiling rectangles (and cuboids) in rectangles (cuboids) with no gaps or overlaps:

    An a × b rectangle can be packed with 1 × n strips if and only if n divides a or n divides b.
    de Bruijn's theorem: A box can be packed with a harmonic brick a × a b × a b c if the box has dimensions a p × a b q × a b c r for some natural numbers p, q, r (i.e., the box is a multiple of the brick.)

    The study of polyomino tilings largely concerns two classes of problems: to tile a rectangle with congruent tiles, and to pack one of each n-omino into a rectangle.

    A classic puzzle of the second kind is to arrange all twelve pentominoes into rectangles sized 3×20, 4×15, 5×12 or 6×10.

    Packing of irregular objects

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    Packing of irregular objects is a problem not lending itself well to closed form solutions; however, the applicability to practical environmental science is quite important. For example, irregularly shaped soil particles pack differently as the sizes and shapes vary, leading to important outcomes for plant species to adapt root formations and to allow water movement in the soil.

    The problem of deciding whether a given set of polygons can fit in a given square container has been shown to be complete for the existential theory of the reals.

    See also

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    Notes

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      Torquato, S.; Jiao, Y. (August 2009). "Dense packings of the Platonic and Archimedean solids". Nature. 460 (7257): 876–879. arXiv:0908.4107. Bibcode:2009Natur.460..876T. doi:10.1038/nature08239. ISSN 0028-0836. PMID 19675649. S2CID 52819935.
    1. ↑ Stein, Sherman K. (March 1995), "Packing tripods", Mathematical entertainments, The Mathematical Intelligencer, 17 (2): 37–39, doi:10.1007/bf03024896, S2CID 124703268. Reprinted in "Circle Packing".
    2. ↑ Stoyan, Y. G.; Yaskov, G. N. (2010). "Packing identical spheres into a cylinder". International Transactions in Operational Research. 17: 51–70. doi:10.1111/j.1475-3995.2009.00733.x.
    3. ↑ Honsberger, Ross (1976). Mathematical Gems II. The Mathematical Association of America. p. 67. ISBN 0-88385-302-7.
    4. ↑ ∃ℝ-Completeness of Two-Dimensional Packing Problems, arXiv:2004.07558.

    References

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    External links

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    Wikimedia Commons has media related to Packing problems.

    Many puzzle books as well as mathematical journals contain articles on packing problems.

    Abstract packing
    Circle packing
    Sphere packing
    Other 2-D packing
    Other 3-D packing
    Puzzles

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