Alphabeta Math
ExampleConstruction: Literature-sourcedVerification: AI-adaptedSession-authored (Fable 5 assisted)precheck passjudge pass (deepseek-v4-pro + gpt-5.6-terra)audited 2026-08-13
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

F[x](x) is the ring of rational functions defined at 0, with maximal ideal generated by x and residue field F

Example

For a field F, F[x](x)={f(x)g(x)F(x):g(0)0}. This is the ring of rational functions defined at 0. Its maximal ideal is generated by x, and its residue field is canonically F.

Facts & Assumptions

Given: A field F and the polynomial ring F[x].

[F1]

Evaluation at 0 is the unique homomorphism F[x]F fixing F and sending x to 0 (Universal property of R[x]: a coefficient homomorphism and the image of x determine a unique ring homomorphism).

[F2]

For gF[x], one has g(0)=0 exactly when x divides g (Factor theorem over a commutative ring).

[F3]

A quotient by an ideal is a field exactly when the ideal is maximal (R/M is a field if and only if M is a maximal ideal).

[F4]

Localising at a prime yields a local ring with the extended prime as maximal ideal, and its residue field is the fraction field of the quotient domain (Rp is local with unique maximal ideal pRp, Rp/pRpFrac(R/p) is the residue field at p).

[F6]

Every maximal ideal of a commutative ring is prime (Every maximal ideal of a commutative ring is prime).

[F7]

A homomorphism that sends every denominator to a unit factors uniquely through the localisation (Universal property of localisation: maps that invert S factor uniquely through S1R).

[F8]

A localisation fraction f/g is zero exactly when some denominator annihilates f (Equality, vanishing, and the kernel of the localisation map).

[F9]

Localisation at a prime ideal P uses the multiplicative set RP (Localisation at a prime ideal: Rp=(Rp)1R).

Verification

technique · direct
1.1

By [F1] and [F2], evaluation at 0 has kernel (x) and is onto. Explicitly, f+(x)f(0) is well defined and has inverse cc+(x), so F[x]/(x)F. Thus [F3] makes (x) maximal, and [F6] makes it prime.

F1F2F3F6algebra
1.2

By [F9], the denominators are the elements outside (x), which are exactly the polynomials g with g(0)0 by [F2]. They are nonzero and hence units in F(x) by [F5], so [F7] gives a map from the localisation to F(x) sending f/g to the same fraction. If its image is zero, then f=0 because [F5] embeds the domain F[x] in its fraction field, and [F8] makes f/g=0 in the localisation. The map is therefore injective, and its image is precisely the displayed fractions, which are exactly those admitting a representative with denominator nonzero at 0.

F2F5F7F8F9
2.1

By [F4], the maximal ideal is (x)F[x](x)=xF[x](x), and the residue field is Frac(F[x]/(x))Frac(F). Every nonzero denominator in the field F is already invertible, so a/b=(ab1)/1 and the last fraction field is canonically F.

F4step 1.1algebra

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · next 3 levels

Direct dependencies and their dependencies through the next three levels: 65 results over 15 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.

Sources