Exterior forms and the exterior derivative
Research context
postgraduate concept · established · As of 2026-10-10
Differential k-forms are smooth alternating covariant tensors.
Key knowledge
Differential k-forms are smooth alternating covariant tensors. Exterior differentiation maps k-forms to (k+1)-forms, satisfies d²=0 and the graded product rule, and commutes with smooth pullback. In coordinates d(sum a-I dx-I)=sum da-I wedge dx-I. The familiar gradient, curl and divergence formulas are coordinate/metric representations of parts of this calculus.
Values and equations
d(alpha wedge beta)=dalpha wedge beta+(-1)^k alpha wedge dbeta; d²=0
- alpha
- Smooth k-form
- beta
- Smooth form of any compatible degree
- d
- Exterior derivative
Conditions and scope
- Wedge products change sign according to the degrees of the factors.
- Exterior differentiation requires smoothness here; weak extensions need separately specified function spaces.
Sources · 1
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Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: §§1.2, 2.1–2.2, 3.1, 11.1–11.2, 12.1–12.2, 13.1, 15.1–15.3, 17.1–17.3; each record narrows its applicable claim. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
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