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.
Direct image of a sheaf along a continuous map
Definition
Let be a continuous map, and let be a presheaf on . The direct image presheaf on is defined on an open set by
If , the restriction map
is the restriction map of for the inclusion .
Thus direct image is just precomposition of the presheaf with the inverse-image map on open sets.
Depends on
Used by
- Twisting the exact sequence of an effective Cartier divisor Corollary
- Derived operations on analytic field sheaves Definition
- Geometric vector bundle with the sections convention Definition
- Higher direct image of a sheaf Definition
- Morphisms of ringed spaces Definition
- Adjunction on a smooth plane quartic: the canonical bundle is the hyperplane bundle Example
- Direct image along an open immersion is restriction-compatible intersection Example
- Dualizing and support shifts on the complex line Example
- A sheaf with no stalks off a closed subset is a pushforward Lemma
- Actual analytic constructible sheaves admit coherent six operations Lemma
- Acyclic product fibers stabilize bounded constructible pullback Hom Lemma
- Affine pushforward algebra localizes Lemma
- Affine pushforward is compatible with sheaf cohomology Lemma
- Arithmetic genus, geometric genus and delta invariants Lemma
- Bounded fibrewise-soft resolutions from a uniform all-sheaf dimension bound Lemma
- Cartesian simplicial sheaves model actual equivariant derived Hom Lemma
- Closed immersion preserves cohomology and coherent pushforward Lemma
- Closed immersions are affine quotients and survive base change Lemma
- Cohomology comparison when higher direct images vanish Lemma
- Compact-support calculus along open and closed embeddings Lemma
- Complex algebraic constructible complexes have finite conical cochain models Lemma
- Derived tensor–Hom and inverse/direct image for field sheaves Lemma
- Direct image preserves sheaves and objectwise algebraic structure Lemma
- Euler characteristic of a closed point, and invariance under an invertible twist Lemma
- Extension by zero and the closed complement: a short exact sequence Lemma
- Finite simplicial constructible sheaves have an actual derived incidence model Lemma
- General linear Stiefel approximations stabilize bounded constructible Hom Lemma
- General linear Stiefel perverse normalization is exact and conservative Lemma
- High-degree section module is finite graded Lemma
- Hypersurface cohomology sequence Lemma
- Local-section formula for derived direct image Lemma
- Locally split Cech nerves give actual derived Cartesian sheaf descent Lemma
- Noetherian devissage for coherent proper pushforward Lemma
- Projection formula for a closed immersion and an invertible sheaf Lemma
- Properness survives composition Lemma
- Pushforward along a closed immersion preserves sheaf cohomology Lemma
- Pushouts of closed immersions exist Lemma
- Schematic closure and agreement on a dense open Lemma
- Shifted smooth complex pullback is exact for the middle perverse t structure Lemma
- Structure sheaf of a quasi-compact quasi-separated morphism is affine-local Lemma
…and 22 more results.
Dependency tree · two levels
4 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- The Stacks Project, Section 6.21: Continuous maps and sheaves (standard reference, not scraped)
- Ravi Vakil, The Rising Sea, Sections 2.2.H and 2.7 (standard reference, not scraped)