Alphabeta Math

Local Coefficients, Twisted Homology, and Duality

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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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✓ 13 results · all verified · 9 also independently AI-judged
Every result on this page is machine-checked by a proof checker and read in full and owner-audited; the judge is an additional, independent cross-model AI review of the proofs. The 4 not AI-judged were verified by owner audit (typically over a confirmed judge false positive), not failures.
1 · Prerequisites
Abstract Algebra
Algebraic Topology
Category Theory
Combinatorics
Homological Algebra
Linear Algebra
Real Analysis
Set Theory
Topology
2 · Logical flowchart

3 · Items

Definition

Fundamental groupoid of a space

Proposition

Vertex groups recover the fundamental group

Definition

Local systems and pullback

Theorem

Local systems correspond to group-ring modules

Definition

Right action on universal-cover chains

Definition

Singular and cellular local chain complexes

Lemma

Twisted boundaries square to zero and ignore lift bases

Definition

Homology and cohomology with local coefficients

Proposition

Functoriality with coefficient morphisms

Theorem

Cellular chains compute local homology

Theorem

Pair exact sequences with local coefficients

Theorem

Excision and Mayer–Vietoris with local coefficients

Theorem

Cellular cochains compute cohomology with local coefficients

Definition

Compactly supported cohomology with local coefficients

Proposition

The orientation system is a local system

Definition

Orientation local system on a manifold with boundary

Lemma

Canonical twisted fundamental classes over compact subsets

Definition

Cup and cap products with local coefficients

Theorem

Poincare duality with the orientation local system

Theorem

Poincare–Lefschetz duality with local coefficients

Lemma

Fiber transport gives the Serre local systems

Sources