Gyration

{{Short description|A rotation in a discrete subgroup of symmetries of the Euclidean plane}}

{{about|rotational symmetry in mathematics|the size measure in structural engineering|radius of gyration|the motion of a charged particle in an magnetic field|cyclotron motion|the tensor of second moments|gyration tensor}}

{{one source |date=May 2024}}

{{Use dmy dates|date=August 2019|cs1-dates=y}}

In geometry, a gyration is a rotation in a discrete subgroup of symmetries of the Euclidean plane such that the subgroup does not also contain a reflection symmetry whose axis passes through the center of rotational symmetry. In the orbifold corresponding to the subgroup, a gyration corresponds to a rotation point that does not lie on a mirror, called a gyration point.

For example, having a sphere rotating about any point that is not the center of the sphere, the sphere is gyrating. If it was rotating about its center, the rotation would be symmetrical and it would not be considered gyration.

References

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{{cite book |authorlink1=Martin Liebeck |author-first1=Martin W. |author-last1=Liebeck |author-first2=Jan |author-last2=Saxl |author-first3=N. J. |author-last3=Hitchin |author-first4=A. A. |author-last4=Ivanov |title=Groups, Combinatorics & Geometry |url=https://books.google.com/books?id=5h84AAAAIAAJ&pg=PA439 |location=Symposium, London Mathematical Society: Symposium on Groups and Combinatorics (1990), Durham |date=1992-09-10 |orig-year=1990 |edition=illustrated |publisher=Cambridge University Press |access-date=2010-04-07 |series=Lecture note series |volume=165 |issn=0076-0552 |isbn=0-52140685-4 }} (489 pages)

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