PlanetMath (more info)
 Math for the people, by the people. Sponsor PlanetMath
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
Owner confidence rating: High Entry average rating: Very high
affine space (Definition)
Definition 1   Let $K$ be a field and let $n$ be a positive integer. In algebraic geometry we define affine space (or affine $n$ -space) to be the set $$\{ (k_1,\ldots,k_n): k_i \in K\}.$$ Affine space is usually denoted by $K^n$ or $\mathbb{A}^n$ (or $\mathbb{A}^n(K)$ if we want to emphasize the field of definition).

In Algebraic Geometry, we consider affine space as a topological space, with the usual Zariski topology (see also algebraic set, affine variety). The polynomials in the ring $K[x_1,\ldots,x_n]$ are regarded as functions (algebraic functions) on $\mathbb{A}^n(K)$ . ``Glueing'' several copies of affine space one obtains a projective space.

Lemma 1   If $K$ is algebraically closed, affine space $\mathbb{A}^n(K)$ is an irreducible algebraic variety.

Bibliography

1
R. Hartshorne, Algebraic Geometry, Springer-Verlag, New York.




Anyone with an account can edit this entry. Please help improve it!

"affine space" is owned by alozano. [ full author list (3) ]
(view preamble | get metadata)

View style:

See Also: projective space, affine variety

Log in to rate this entry.
(view current ratings)

Cross-references: variety, algebraic, irreducible, algebraically closed, projective space, algebraic functions, functions, ring, polynomials, affine variety, algebraic set, Zariski topology, topological space, algebraic geometry, integer, positive, field
There are 11 references to this entry.

This is version 4 of affine space, born on 2005-05-05, modified 2006-02-21.
Object id is 7013, canonical name is AffineSpace3.
Accessed 6981 times total.

Classification:
AMS MSC14-00 (Algebraic geometry :: General reference works )
 14R10 (Algebraic geometry :: Affine geometry :: Affine spaces )

Pending Errata and Addenda
None.
[ View all 1 ]
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | add derivation | add example | add (any)