In algebraic geometry, the homogeneous coordinate ringR of an algebraic variety V given as a subvariety of projective space of a given dimension N is by definition the quotient ring
R = K[X0, X1, X2, ..., XN] / I
where I is the homogeneous ideal defining V, K is the algebraically closed field over which V is defined, and
K[X0, X1, X2, ..., XN]
is the polynomial ring in N + 1 variables Xi. The polynomial ring is therefore the homogeneous coordinate ring of the projective space itself, and the variables are the homogeneous coordinates, for a given choice of basis (in the vector space underlying the projective space). The choice of basis means this definition is not intrinsic, but it can be made so by using the symmetric algebra.
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In algebraic geometry, the homogeneouscoordinatering R of an algebraic variety V given as a subvariety of projective space of a given dimension N is...
multiplication may not be commutative. For the general ring A, a projective line over A can be defined with homogeneous factors acting on the left and the projective...
between homogeneous polynomials and projective varieties (cf. Homogeneouscoordinatering.) The above definitions have been generalized to rings graded...
] / I {\displaystyle k[x_{0},\ldots ,x_{n}]/I} is called the homogeneouscoordinatering of X. Basic invariants of X such as the degree and the dimension...
For a projective variety, there is an analogous ring called the homogeneouscoordinatering. Those rings are essentially the same things as varieties: they...
homogeneouscoordinate system is one where only the ratios of the coordinates are significant and not the actual values. Some other common coordinate...
curve, then the canonical ring is again the homogeneouscoordinatering of the image of the canonical map. In general, if the ring above is finitely generated...
function on X is of the form g/h for some homogeneous elements g, h of the same degree in the homogeneouscoordinatering k [ X ¯ ] {\displaystyle k[{\overline...
transform. The goal of the theory is to prove results on the homogeneouscoordinatering of the embedded abelian variety A, that is, set in a projective...
such embedding of C and the minimal free resolution for its homogeneouscoordinatering, for the minimum index i for which βi, i + 1 is zero, then the...
set, whose homogeneouscoordinatering is an integral domain, the projective coordinates ring being defined as the quotient of the graded ring or the polynomials...
as the Hilbert polynomial of the homogeneouscoordinatering of V. Polynomial rings and their quotients by homogeneous ideals are typical graded algebras...
example Nagata's compactification theorem. Cox ring A generalization of a homogeneouscoordinatering. See Cox ring. crepant A crepant morphism f : X → Y {\displaystyle...
integral over R. The integral closure of the homogeneouscoordinatering of a normal projective variety X is the ring of sections ⨁ n ≥ 0 H 0 ( X , O X ( n...
for invariant theory, starting from the work of Hodge on the homogeneouscoordinatering of the Grassmannian and further explored by Gian-Carlo Rota with...
}=\xi _{1}^{\alpha _{1}}\cdots \xi _{n}^{\alpha _{n}}.} The highest homogeneous component of the symbol, namely, σ ( x , ξ ) = ∑ | α | = m a α ( x )...
commutative ring. This construction builds a projective algebraic variety together with a very ample line bundle whose homogeneouscoordinatering is the original...
Castelnuovo–Richmond–Igusa quartic Noether–Castelnouvo theorem Homogeneouscoordinatering Riemann–Roch theorem for surfaces Italian school of algebraic...
vector spaces based on different kinds of scalars: real coordinate space or complex coordinate space. Vector spaces generalize Euclidean vectors, which...
mathematics, the ring of polynomial functions on a vector space V over a field k gives a coordinate-free analog of a polynomial ring. It is denoted by...
vector space m/m2 over the residue field. Cox ring A Cox ring is a sort of universal homogeneouscoordinatering for a projective variety. decomposable A module...
} Equivalently, it can be checked that: The elements of the affine coordinatering A ( X ) = k [ x 1 , … , x n ] / I ( X ) {\displaystyle A(X)\,=\,k[x_{1}...
In mathematics, the real coordinate space or real coordinate n-space, of dimension n, denoted Rn or R n {\displaystyle \mathbb {R} ^{n}} , is the set...
all homogeneous polynomials vanishing on V. For any projective algebraic set V, the coordinatering of V is the quotient of the polynomial ring by this...
Q[x, y]/(x2 + y2 − 1) is not a UFD, but the ring Q(i)[x, y]/(x2 + y2 − 1) is. Similarly the coordinatering R[X, Y, Z]/(X2 + Y2 + Z2 − 1) of the 2-dimensional...
{\displaystyle [W]} . We now define a coordinate atlas. For any n × k {\displaystyle n\times k} homogeneouscoordinate matrix W {\displaystyle W} , we can...