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.
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These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Strong Constraint DFT NS NS Action And Section Reduction
Smooth ten-dimensional massless NS–NS fields in a local doubled chart, subject to the pairwise strong constraint and a fixed supergravity section; no RR fields, localized sources, loops, higher derivatives, strong-constraint-violating twists, global T-fold existence, or full string-CFT equivalence.
Statement
Let and use doubled coordinates , , all with length dimension, with dimensionless and inverse-length derivatives. Let be a symmetric generalized metric satisfying , and let be the dimensionless generalized dilaton. Require every field, gauge parameter, and product of such objects to obey the strong constraint and . Whenever a trivial parameter is used in the gauge-algebra statement, also require its scalar potential to belong to this strongly constrained collection. With compactly supported gauge parameters or vanishing boundary flux, the two-derivative NS–NS DFT action
is invariant under generalized diffeomorphisms, and their gauge algebra closes modulo trivial parameters. Its integrand has dimension length, so the full doubled integral has dimension length after the factor ; the section statement below divides by the dual-coordinate volume of dimension length. On a fixed local supergravity section , set in the string-frame convention, parameterize by and , and set . The action per unit dual-coordinate volume then reduces, up to a total derivative, to the dimensionless source-free leading tree-level two-derivative string-frame NS–NS action. This is a local massless-field result; it does not assert global T-fold existence, independent dependence on all doubled coordinates, RR/source terms, higher-derivative corrections, string loops, or an uplift for every gauged supergravity.
Statement references
Facts & Assumptions
Given: Smooth ten-dimensional Lorentzian , smooth and , the DFT field and transformation conventions, the pairwise strong constraint (including any scalar potential used for a trivial parameter), a fixed local physical section, and, for the integrated gauge-invariance claim, a compactly supported gauge parameter or vanishing boundary flux for the gauge-variation divergence. The section reduction is stated modulo the total derivatives specified in [F4].
Strong Constraint DFT Generalized Metric Data: , is off-diagonal, is the block generalized metric built from a local metric and , and on the physical section; the stated strong constraint applies to all fields, gauge parameters, and products.
Strong Constraint DFT Generalized Gauge Algebra Closure: under [F1]'s strong constraint, generalized diffeomorphisms close with the defined C-bracket modulo parameters whose potentials are themselves in the strongly constrained scalar collection and which act trivially.
Strong Constraint DFT Scalar and Action Gauge Invariance: the generalized-metric action is up to an explicit total divergence, and is invariant up to boundary terms because .
Strong Constraint DFT Supergravity Section Reduction: on a product coordinate domain with , the normalized action divided by reduces on to the string-frame NS–NS action, modulo the supplier's explicit total derivatives and wherever the integrals exist. The NS–NS action is adopted in [A2].
Supergravity Conventions And Normalizations: in ten dimensions is the string-frame metric, the signature is mostly plus, , and .
Ten Dimensional NS NS Supergravity Action: adopt the source-free leading tree-level two-derivative NS–NS action in terms of , , and , with no RR fields, localized sources, loops, or higher powers of .
Proof
By [F2], the generalized diffeomorphism commutator closes modulo trivial parameters on the DFT data in [F1]. By [F3], the action density changes only by a total divergence under the same strong constraint. The compact-support or boundary condition in the Given clause removes the integrated divergence, so the DFT action is invariant.
On the section , evaluate the local action per unit dual-coordinate volume on a product with , wherever the integrals exist. The section density is independent of , so . This expression is independent of the chosen finite positive dual volume; it is the meaning of the local per-unit-volume action, without an infinite-volume quotient. Apply [F4]'s section calculation to this expression with [A1]–[A2]. It gives the string-frame action density and normalization in the Statement, with the stated total-derivative qualification. Combining this result with step 1.1 establishes the DFT claim under the adopted NS–NS action premise; this proof does not derive that physical premise or claim independent proof approval for its supplier.