3D Isometries That Leave Origin Fixed
The isometries of R3 that leave the origin fixed, forming the group O(3,R), can be categorized as follows:
- SO(3,R):
- identity
- rotation about an axis through the origin by an angle not equal to 180°
- rotation about an axis through the origin by an angle of 180°
- the same with inversion (x is mapped to −x), i.e. respectively:
- inversion
- rotation about an axis by an angle not equal to 180°, combined with reflection in the plane through the origin perpendicular to the axis
- reflection in a plane through the origin
The 4th and 5th in particular, and in a wider sense the 6th also, are called improper rotations.
See also the similar overview including translations.
Read more about this topic: Point Groups In Three Dimensions
Famous quotes containing the words leave, origin and/or fixed:
“You’d leave your own mother here, if the rules called for it.”
—Michael Wilson (1914–1978)
“Art is good when it springs from necessity. This kind of origin is the guarantee of its value; there is no other.”
—Neal Cassady (1926–1968)
“Every morning I woke in dread, waiting for the day nurse to go on her rounds and announce from the list of names in her hand whether or not I was for shock treatment, the new and fashionable means of quieting people and of making them realize that orders are to be obeyed and floors are to be polished without anyone protesting and faces are to be made to be fixed into smiles and weeping is a crime.”
—Janet Frame (b. 1924)