Greyship

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A greyship

A greyship is a spaceship which contains a region of density 1/2 (usually the zebra stripes agar) that can be extended to an arbitrary size both horizontally and vertically.

The first greyships, with speed c/2 orthogonal, were found by Hartmut Holzwart and Jason Summers in 2005.[1][2][3] Since then greyships have been found for speeds c/3, c/4, c/5, and 2c/5.[4]

In 2020 a burst of activity by Keith Amling, Hartmut Holzwart, and Matthias Merzenich produced a considerable amount of new greyship technology.[5]

Types of greyships

Most known greyship components use the stripes agar and travel with the grain (parallel to the stripes). There are also some known against-the-grain greyships, in which the stripes are perpendicular to the direction of travel; however, these are only known for a speed of c/2.[6] A hybrid greyship, containing both with-the-grain and against-the-grain components, is possible as well.

Other than the stripes agar, there are a few known greyships that use the chicken wire agar[7], and some with other types of discontinuity.[8][9] A looser definition of greyship may also include ships with extensible, high-density agars of higher periods.

See also

References

  1. Dave Greene (July 9, 2005). "c/2 and 2c/4 "greyships"". Game of Life News. Retrieved on February 24, 2018.
  2. Dave Greene (September 6, 2005). "Greyship Update". Game of Life News. Retrieved on February 24, 2018.
  3. Dave Greene (December 10, 2005). "Holiday Greyships -- Grey No Longer!". Conway's Life: Work in Progress (weblog). Retrieved on February 24, 2018.
  4. Dave Greene (January 10, 2011). "First c/5 greyship, and a new c/3". Game of Life News. Retrieved on February 24, 2018.
  5. Matthias Merzenich (January 1, 2021). Re: PotY 2020 Nomination Thread (discussion thread) at the ConwayLife.com forums
  6. Dave Greene (December 16, 2005). "New perpendicular greyships". Game of Life News. Retrieved on February 24, 2018.
  7. Dave Greene (April 3, 2006). "Chicken-Wire-Agar Greyships". Game of Life News. Retrieved on February 24, 2018.
  8. Dave Greene (December 16, 2005). "Hybrid greyships (perpendicular and parallel stripes)". Game of Life News. Retrieved on February 24, 2018.
  9. Dave Greene (December 18, 2005). "Fixed-Width and Slipping-Stripe Greyships". Game of Life News. Retrieved on February 24, 2018.

External links