Affine schemes retain local and nilpotent structure
Research context
postgraduate concept · established · As of 2026-10-10
An affine scheme Spec(R) pairs the space of prime ideals with a structure sheaf.
Key knowledge
An affine scheme Spec(R) pairs the space of prime ideals with a structure sheaf. On the standard open D(f), sections are R-f, and the stalk at a prime p is R-p. This retains arithmetic and nilpotent information that a set of field-valued points loses: Spec(k[epsilon]/epsilon²) has one point but a nonzero nilpotent in its ring. A general scheme is locally affine and is glued compatibly.
Values and equations
O_Spec(R)(D(f))=R_f; O_Spec(R),p=R_p
- D(f)
- Primes not containing f
- R_f
- Localization obtained by inverting f
- R_p
- Localization at the prime p
Conditions and scope
- R is a commutative ring with identity; localizations and sheaf restrictions are part of the construction.
- A scheme need not be reduced, irreducible, finite type or smooth.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: Section 26.5: standard opens D(f), sheaf values R-f and stalks R-p. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
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