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:

    We shall never resolve the enigma of the relation between the negative foundations of greatness and that greatness itself.
    Jean Baudrillard (b. 1929)

    A theory of the middle class: that it is not to be determined by its financial situation but rather by its relation to government. That is, one could shade down from an actual ruling or governing class to a class hopelessly out of relation to government, thinking of gov’t as beyond its control, of itself as wholly controlled by gov’t. Somewhere in between and in gradations is the group that has the sense that gov’t exists for it, and shapes its consciousness accordingly.
    Lionel Trilling (1905–1975)

    Man is clearly made to think. It is his whole dignity and his whole merit; and his whole duty is to think as he ought. And the order of thought is to begin with ourselves, and with our Author and our end.
    Blaise Pascal (1623–1662)