Value Group
The units D* of D comprise a group under multiplication, which is a subgroup of the units F* of F, the nonzero elements of F. These are both abelian groups, and we can define the quotient group V = F*/D*, which is the value group of D. Hence, we have a group homomorphism ν from F* to the value group V. It is customary to write the group operation in V as +.
We can turn V into a totally ordered group by declaring the residue classes of elements of D as "positive". More precisely, V is totally ordered by defining if and only if where and are equivalence classes in V.
Read more about this topic: Valuation Ring
Famous quotes containing the word group:
“Just as a person who is always asserting that he is too good-natured is the very one from whom to expect, on some occasion, the coldest and most unconcerned cruelty, so when any group sees itself as the bearer of civilization this very belief will betray it into behaving barbarously at the first opportunity.”
—Simone Weil (19101943)
“We begin with friendships, and all our youth is a reconnoitering and recruiting of the holy fraternity they shall combine for the salvation of men. But so the remoter stars seem a nebula of united light, yet there is no group which a telescope will not resolve; and the dearest friends are separated by impassable gulfs.”
—Ralph Waldo Emerson (18031882)