Indefinite Form
There are as many as eight different double covers of O(p, q), for p, q ≠ 0, which correspond to the extensions of the center (which is either C2 × C2 or C4) by C2. Only two of them are pin groups—those that admit the Clifford algebra as a representation. They are called Pin(p, q) and Pin(q, p) respectively.
Read more about this topic: Pin Group
Famous quotes containing the words indefinite and/or form:
“As they are not seen on their way down the streams, it is thought by fishermen that they never return, but waste away and die, clinging to rocks and stumps of trees for an indefinite period; a tragic feature in the scenery of the river bottoms worthy to be remembered with Shakespeare’s description of the sea-floor.”
—Henry David Thoreau (1817–1862)
“Reverence is the highest quality of man’s nature; and that individual, or nation, which has it slightly developed, is so far unfortunate. It is a strong spiritual instinct, and seeks to form channels for itself where none exists; thus Americans, in the dearth of other objects to worship, fall to worshipping themselves.”
—Lydia M. Child (1802–1880)