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 between, relation and/or order:

    There is a certain standard of grace and beauty which consists in a certain relation between our nature, such as it is, weak or strong, and the thing which pleases us. Whatever is formed according to this standard pleases us, be it house, song, discourse, verse, prose, woman, birds, rivers, trees, room, dress, and so on. Whatever is not made according to this standard displeases those who have good taste.
    Blaise Pascal (1623–1662)

    The whole point of Camp is to dethrone the serious. Camp is playful, anti-serious. More precisely, Camp involves a new, more complex relation to “the serious.” One can be serious about the frivolous, frivolous about the serious.
    Susan Sontag (b. 1933)

    Children and old people and the parents in between should be able to live together, in order to learn how to die with grace, together. And I fear that this is purely utopian fantasy ...
    M.F.K. Fisher (1908–1992)