Alphabeta Math
PropositionStatement: AI-adaptedProof: AI-adaptedPipeline-generatedprecheck passverified 2026-10-22 (gpt-6.1-sol)
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.

Chern–Simons boundary variation and BF equations

Physical scope

Pure mathematics; no physical premises or empirical claim.

Statement

Assume the Axiom of Countable Choice ACω. Let M be a compact oriented smooth three-manifold with boundary, g a finite-dimensional real Lie algebra with invariant nondegenerate symmetric pairing, and A∈Ω1(M;g) a smooth connection in a fixed trivialization. For an arbitrary smooth variation α∈Ω1(M;g), the Chern–Simons first variation is

δCS⁡A(α)=2∫M⟨α∧FA⟩−∫∂M⟨A∧α⟩,

where ∂M has the outward-normal-first orientation. Thus the boundary term is part of the variation; the bulk Euler equation is FA=0 when variations are compactly supported in int⁡M (or when boundary data make the boundary variation vanish). For B∈Ω1(M;g) the BF action has first variation

δBF⁡(B,A)(β,α)=∫M⟨β∧FA⟩+∫M⟨α∧DAB⟩−∫∂M⟨B∧α⟩,

so interior-compact variations give the equations FA=0 and DAB=0. No boundary condition is imposed by these bulk equations.

For λ∈R fixed, the boundary potential current of λCS⁡ is θA(α)=−λ⟨A∧α⟩. On a compact oriented smooth surface Σ (with smooth boundary allowed), put AΣ=Ω1(Σ;g) and identify each tangent space with Ω1(Σ;g). For a∈AΣ define ΘΣ∣a(α)=∫Σθa(α), and let ΩΣ=dAΣΘΣ. The restriction to the flat-connection solution space, wherever it is smooth, is the possibly degenerate presymplectic form. Explicitly, on tangent vectors α1,α2 it is the constant closed form

ΩΣ(α1,α2)=−2λ∫Σ⟨α1∧α2⟩.

At a flat connection a (Fa=0), tangent variations α to the flat-connection equations satisfy Daα=0. For an infinitesimal gauge parameter ϵ∈C∞(Σ;g), the gauge direction is Daϵ and

ΩΣ(Daϵ,α)=−2λ∫∂Σ⟨ϵ,α⟩.

Consequently gauge parameters vanishing on ∂Σ generate null directions on the linearized flat locus. If ϵ is field-independent, the displayed boundary variation is δQϵ for Qϵ(a)=−2λ∫∂Σ⟨ϵ,a⟩. For λ≠0, nonzero boundary parameters need not be null and can carry such charges when the boundary conditions permit them; no charge algebra or integrability assertion for field-dependent parameters is made. If λ=0, the displayed ΘΣ, ΩΣ and Qϵ vanish identically, and every gauge direction on the linearized flat locus is null.

Facts & Assumptions

Given: A compact oriented smooth three-manifold M with boundary, a finite-dimensional real Lie algebra g with the invariant nondegenerate pairing in the action definition, smooth fields A,B and variations α,β, and the stated ACω assumption.

[A1]

The Axiom of Countable Choice (ACω): ACω says every countable family of nonempty sets has a choice function.

[F1]

Chern–Simons and BF action data: FA=dA+12[A,A], DAX=dX+[A,X], CS⁡(A)=∫M⟨A∧dA+13A∧[A,A]⟩, and BF⁡(B,A)=∫M⟨B∧FA⟩.

[F2]

The general Stokes theorem: under ACω, for an oriented smooth n-manifold with boundary and a compactly supported smooth (n−1)-form η, ∫Mdη=∫∂Mj∗η with outward-normal-first boundary orientation. Here compactness of M makes all smooth forms used below compactly supported.

Proof

1.1givenF1algebra

Differentiate the Chern–Simons integrand along A+sα. The quadratic term contributes ⟨α∧dA+A∧dα⟩. For the cubic term, the graded bracket and invariant pairing give the cyclic identities ⟨A∧[α,A]⟩=⟨α∧[A,A]⟩ and ⟨A∧[A,α]⟩=⟨α∧[A,A]⟩ for degree-one A,α. Thus the three differentiated terms in 13⟨A∧[A,A]⟩ are equal, and their average is ⟨α∧[A,A]⟩. The full unintegrated variation is ⟨α∧dA+A∧dα+α∧[A,A]⟩.

1.2F1algebra

Differentiate FA+sα at s=0; bilinearity of the bracket gives δFA=DAα. Thus the BF variation before integration by parts is ∫M⟨β∧FA+B∧DAα⟩.

2.1A1F1F2step 1.1algebra

The graded Leibniz rule gives d⟨A∧α⟩=⟨dA∧α⟩−⟨A∧dα⟩. Since a two-form commutes with a one-form under wedge, ⟨A∧dα⟩=⟨α∧dA⟩−d⟨A∧α⟩. Substitute this into step 1.1, combine 2dA+[A,A]=2FA, and apply [F2] to obtain the stated Chern–Simons formula, including its boundary sign.

3.1A1F1step 2.1construct

For variations compactly supported in int⁡M, the boundary term in step 2.1 is zero. If stationarity holds for every such α, then ∫M⟨α∧FA⟩=0 for every local test variation. If FA were nonzero at some point, nondegeneracy of the pairing would select an algebra element pairing nontrivially with one component; continuity preserves its sign on a smaller chart, and a nonnegative bump supported there would make the integral nonzero. Hence FA=0 on int⁡M.

3.2step 2.1algebra

For constant tangent vectors α1,α2 on the affine space AΣ, differentiating the potential current θA(α)=−λ⟨A∧α⟩ from step 2.1 gives Dα1Θ(α2)=−λ∫Σ⟨α1∧α2⟩ and Dα2Θ(α1)=−λ∫Σ⟨α2∧α1⟩. The field-space exterior derivative is their difference; antisymmetry of the wedge gives ΩΣ=−2λ∫Σ⟨α1∧α2⟩. Its coefficients are constant, so its field-space exterior derivative is zero.

4.1A1F1F2step 1.2step 2.1step 3.1algebra

Invariance of the pairing makes DA obey the graded Leibniz rule on paired forms. Therefore d⟨B∧α⟩=⟨DAB∧α⟩−⟨B∧DAα⟩. As in step 2.1, the two-form DAB commutes under wedge with α. Apply [F2] to obtain the stated BF formula. For variations supported in the interior the boundary integral vanishes. Independent compactly supported β and α then test FA and DAB separately; the local nondegenerate-pairing bump argument in step 3.1 shows each must vanish.

4.2A1F1F2step 3.2algebra

At a flat a, Da2ϵ=[Fa,ϵ]=0, so Daϵ is tangent to the flat locus. For a tangent α, Daα=0. Invariance of the pairing yields d⟨ϵ,α⟩=⟨Daϵ∧α⟩+⟨ϵ,Daα⟩. Integrating and applying [F2] on Σ gives ∫Σ⟨Daϵ∧α⟩=∫∂Σ⟨ϵ,α⟩, which proves the gauge-contraction formula. If ϵ∣∂Σ=0, this contraction vanishes for every tangent α. If ϵ is fixed under variation, direct differentiation of Qϵ(a)=−2λ∫∂Σ⟨ϵ,a⟩ gives exactly the same contraction.

5.1step 4.2constructalgebra∎

For λ≠0, nonzero boundary parameters can in fact give nonzero contractions. Take g=R with pairing multiplication, the unit disk Σ⊂R2 with its standard orientation, a=0, ϵ(x,y)=x, and α=dy. Then Fa=0, Daα=d(dy)=0, and Daϵ=dx. Polar coordinates give ∫Σdx∧dy=∫02π∫01r dr dθ=π, so ΩΣ(Daϵ,α)=−2λπ≠0 when λ≠0. This establishes the stated possibility without asserting that every nonzero boundary parameter has a nonzero charge. If λ=0, the formulas for ΘΣ, ΩΣ and Qϵ all have the common factor λ and vanish; hence every gauge direction is null in this case.

Depends on

Dependency tree · 2 levels

Sources