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.
Equivariant elliptic-complex index character and fixed-component formula
Statement
Assume full AC. Let , , act smoothly by isometries on a compact smooth manifold without boundary. Let be smooth finite-rank Hermitian complex bundles and first-order differential maps with , setting . Their positive-frequency symbols use . Assume the symbol sequence is exact for every nonzero real cotangent vector. A jointly smooth unitary bundle action has maps , with and ; set and require .
Write , let be its formal adjoint for the invariant metrics and Riemannian volume, and put . Its even-to-odd symbol defines the compact-support class . The cohomology groups are finite dimensional. Define , where is the Grothendieck ring of finite-dimensional continuous complex representations.
For any , write for its finitely many connected fixed components, , , and for extension of covectors by zero on . Put and . Then
For a symbol on the -fixed base, means the compact-support relative Chern character weighted by the eigenvalue of on each eigenbundle; for an absolute virtual bundle , . The Todd class is in formal Chern roots, truncated in each degree. The integral is the oriented compact-support cohomological pairing on the cotangent bundle, oriented by . The denominator has nonzero degree-zero term , so its positive-degree part is inverted by a finite nilpotent series. Its full characteristic class is retained for a positive-dimensional component. The degree-zero value of is the trace at ; it is distinct from the degree-zero rank of a Borel equivariant Chern character.
At an element where the fixed locus changes, the formula uses that element's actual fixed components and normal bundles. It applies also at , when and the normal denominator is ; it asserts no transversally elliptic distribution formula. If the fixed components are isolated points, it specializes to
This isolated-point assertion also holds assuming only countable choice, provided every fixed point is simple and the nonnegative selfadjoint Hodge realization of has discrete spectrum, smooth eigensections, trace-class heat operators with smooth kernels for positive time, finite-dimensional cohomology, and zero eigenspace canonically isomorphic to that cohomology. Thus the earlier spectral isolated-point case retains its weaker choice assumption.
Statement references
Equivariant elliptic-complex index and character
Equivariant compact-support symbol classes and the normal Koszul class
Analytic symbol index, normal embedding compatibility and ordinary pushforward
Fixed-inclusion localization for equivariant compact symbol classes
Trace-weighted compact symbol character and the cotangent pushforward
Atiyah–Singer I, §§4–9: analytic symbol index and the embedding method
Segal, §§2–4: fixed-inclusion localization in equivariant K-theory
Yi, Theorem 1.1 and §§2–5: the separate simple isolated-point heat-kernel formula
Facts & Assumptions
Given: The equivariant first-order elliptic complex and invariant metrics in the Statement; full AC for the general fixed-component assertion, or the separately stated countable-choice Hodge heat hypotheses for its isolated-point branch.
The index and its character are the alternating cohomology representation and trace. Equivariant elliptic-complex index and character
The positive-frequency even-to-odd symbol gives a compact-support equivariant triple, and the doubled real normal uses the exterior-multiplication Koszul convention. Equivariant compact-support symbol classes and the normal Koszul class
Compact-symbol analytic realization identifies the complex's index with . Analytic Gysin compatibility holds for a real equivariant embedding. On a base fixed by , evaluation is the eigenvalue-weighted ordinary topological pushforward. The full analytic calculus, controlled excision, positive-order associated product and orthogonal Bott normalization are proved in its prerequisite chain. Analytic symbol index, normal embedding compatibility and ordinary pushforward
After localization at , the fixed inclusion reconstructs every class by . It proves smoothness and finiteness of the actual fixed components, the normal Koszul self-intersection, and invertibility of the normal class. Fixed-inclusion localization for equivariant compact symbol classes
The trace-weighted ordinary compact-symbol pushforward is the cotangent integral of its relative Chern character times , with precisely the stated orientation. It respects localized quotients and retains the full normal characteristic denominator. Trace-weighted compact symbol character and the cotangent pushforward
With countable choice and the stated Hodge heat data, simple fixed points have heat-supertrace limit . Relative tangent-groupoid heat-trace limit at simple fixed points
Full AC is inherited from the new analytic and topological prerequisites for the general formula. The Axiom of Choice
Only countable choice is used through the original local heat supplier in the isolated-point spectral branch. The Axiom of Countable Choice ()
Proof
Given: The hypotheses and exact conventions in the Statement.
Put at a nonzero real covector. The complex identity gives . The positive-frequency symbol of the formal adjoint is by integration by parts, so the symbol of is . Its square is ; a vector in its kernel is killed by both and , hence belongs to and is orthogonal to that image, so is zero. Thus its even-to-odd block is invertible off the zero section and represents in [F2]. By [L1] the cohomology is finite dimensional and its alternating representation is exactly . This uses the general matrix-symbol analytic chain and does not assume a Clifford-module reduction.
Apply [L2] to this actual . Let in the localized compact-support group of . Its reconstruction is . The analytic index in [L1] is -linear and its Gysin compatibility applies to the real embedding , with exactly the doubled-real Koszul normal used by [L2]. Applying that homomorphism, and then evaluating the localized representations at , gives . The sum is finite; all denominators lie in , so evaluation is defined.
The closure of the cyclic group generated by fixes pointwise. The weightwise assertion in [L1] expresses each character on the right of step 2.1 as the weighted ordinary topological pushforward of . Apply [L3]. The relative character is multiplicative by an absolute bundle class, so . Its compact support is inherited from the restricted symbol; the other factors are pulled back from compact . The resulting cotangent integral is precisely the displayed term. Sum over to prove the general formula.
The normal has no -fixed vector by [L2], so the constant term of is the nonzero determinant . Orthogonality makes it positive: conjugate nonreal eigenvalues give positive paired factors, and the only possible real eigenvalue different from is . Positive-degree cohomology of compact is nilpotent by its finite dimension, so dividing by that constant and taking a finite geometric series defines the inverse. If is a point its Todd factor is and its symbol triple is the virtual graded fiber, so step 3.1 gives the isolated formula. Empty fixed loci give the empty sum, rank-zero normals give denominator , and the identity element uses . At an element with larger fixed locus the same proof uses its larger tangent fixed subspace, so no zero normal eigenvalue is retained as a denominator.
For the separate countable-choice branch, assume only its stated spectral data. The unitary action commutes with and hence with and . On each positive -eigenspace with eigenvalue , the map is an equivariant isomorphism between even and odd parity. Their traces therefore cancel. Trace-classness makes the heat trace series absolutely convergent, so these cancellations can be summed. The zero eigenspace is the cohomology by the branch's Hodge hypothesis, giving for every . The limit in [L4] proves the isolated-point formula under [A2], independently of [A1] and the general-branch steps. Thus the original weaker-choice spectral assertion is retained as well as the full fixed-component claim.
Depends on
Equivariant elliptic-complex index and character
Relative tangent-groupoid heat-trace limit at simple fixed points
The Axiom of Countable Choice ()
The Axiom of Choice
Equivariant compact-support symbol classes and the normal Koszul class
Analytic symbol index, normal embedding compatibility and ordinary pushforward
Fixed-inclusion localization for equivariant compact symbol classes
Trace-weighted compact symbol character and the cotangent pushforward
Dependency tree · 2 levels
Sources
- M. F. Atiyah and I. M. Singer, The Index of Elliptic Operators: I, §§4–9
- Graeme Segal, Equivariant K-theory, §§2–4
- Peter B. Gilkey, Invariance Theory, the Heat Equation, and the Atiyah-Singer Index Theorem, first edition
- Zelin Yi, A Groupoid Proof of the Lefschetz fixed point formula
- Nicole Berline, Ezra Getzler, and Michèle Vergne, Heat Kernels and Dirac Operators
- J. L. Heitsch, The Lefschetz Principle, Fixed Point Theory, and Index Theory