Alphabeta Math
DefinitionDefinition: Literature-sourcedProof: Not applicableSession-authored (Fable 5 assisted)judge pass (deepseek-v4-pro + claude-opus-5[1m])audited 2026-08-24
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.

The tangent plane of a regular surface patch

Definition

Let (D,φ) be a regular parametrized surface patch (Regular parametrized surface patches on compact Jordan parameter regions) and let p=φ(u,v) with (u,v)D. At an interior parameter point, the tangent plane is span{φu,φv}.

The two spanning vectors are linearly independent because their cross product is nonzero (The squared cross-product norm is the Gram determinant of two vectors), so this is a two-dimensional linear subspace of R3 (Linear combination of a finite list, and the span span(S) as the smallest linear subspace containing S). The affine tangent plane through p is p+span{φu,φv}.

Depends on

Used by

Dependency tree · two levels

20 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