Point Groups in Three Dimensions - Relation Between Orbifold Notation and Order

Relation Between Orbifold Notation and Order

The order of each group is 2 divided by the orbifold Euler characteristic; the latter is 2 minus the sum of the feature values, assigned as follows:

  • n without or before * counts as (n−1)/n
  • n after * counts as (n−1)/(2n)
  • * and x count as 1

This can also be applied for wallpaper groups and frieze groups: for them, the sum of the feature values is 2, giving an infinite order; see orbifold Euler characteristic for wallpaper groups

Read more about this topic:  Point Groups In Three Dimensions

Famous quotes containing the words relation and/or order:

    The foregoing generations beheld God and nature face to face; we, through their eyes. Why should not we also enjoy an original relation to the universe? Why should not we have a poetry and philosophy of insight and not of tradition, and a religion by revelation to us, and not the history of theirs?
    Ralph Waldo Emerson (1803–1882)

    The herd of mankind can hardly be said to think; their notions are almost all adoptive; and, in general, I believe it is better that it should be so; as such common prejudices contribute more to order and quiet, than their own separate reasonings would do, uncultivated and unimproved as they are.
    Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)