There are infinitely many 3D point groups; in crystallography, however, they are restricted to be compatible with the discrete translation symmetries of a crystal lattice. This crystallographic restriction of the infinite families of general point groups results in 32 crystallographic point groups.
The point groups are denoted by their component symmetries. There are a few standard notations used by crystallographers, mineralogists, and physicists.
For the correspondence of the two systems below, see crystal system.
In Schönflies notation, point groups are denoted by a letter symbol with a subscript. The symbols used in crystallography mean the following:
Due to the crystallographic restriction theorem, n = 1, 2, 3, 4, or 6.
The correspondence between the three notations is:
|4/m mm||D4h||*224||6/m mm||D6h||*226|
WIPO PUBLISHES PATENT OF TOPCON FOR "POINT GROUP DATA PROCESSING DEVICE, POINT GROUP DATA PROCESSING SYSTEM, POINT GROUP DATA PROCESSING METHOD AND POINT GROUP DATA PROCESSING PROGRAM" (JAPANESE INVENTORS)
Jan 04, 2012; GENEVA, Jan. 4 -- Publication No. WO/2011/162388 was published on Dec. 29. Title of the invention: "POINT GROUP DATA PROCESSING...
US Patent Issued to Okuma on Sept. 7 for "Program and Method for Generating Approximate Curve from Approximate Point Group Data" (Japanese Inventor)
Sep 08, 2010; ALEXANDRIA, Va., Sept. 8 -- United States Patent no. 7,792,603, issued on Sept. 7, was assigned to Okuma Corp. (Aichi, Japan)....
WIPO ASSIGNS PATENT TO KABUSHIKI KAISHA TOPCON FOR "POINT GROUP DATA PROCESSING DEVICE, POINT GROUP DATA PROCESSING METHOD, AND POINT GROUP DATA PROCESSING PROGRAM" (JAPANESE, SWISS INVENTORS)
Jun 22, 2011; GENEVA, June 22 -- Publication No. WO/2011/070927 was published on June 16. Title of the invention: "POINT GROUP DATA PROCESSING...