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 graph of a continuous function on a closed nondegenerate rectangle in has content zero in
Statement
Let , let be a closed nondegenerate rectangle, and let be continuous. Its graph has content zero in .
Facts & Assumptions
Given: as stated.
is compact and uniformly continuous (Heine-Borel in : with the Euclidean metric a subset of is compact if and only if it is closed and bounded, and the proof by bisection uses no choice principle; the same holds on the real line, Heine-Cantor: a continuous map from a compact metric space to any metric space is uniformly continuous, Continuity of a map between metric spaces, at a point and globally, in the - form).
Grid cells and cube volumes are Grid partitions of a rectangle in , their cells, refinements and mesh and Axis-parallel rectangles in and their volume.
Proof
Given , choose a uniform coordinate grid with cell widths at most , where uniform continuity makes the oscillation of on each cell below a vertical amount . Since is nondegenerate, the grid may be chosen so that the number of cells satisfies for a constant depending only on .
One horizontal cube footprint of side covers each domain cell. Above it, stack -cubes of side across the graph's vertical range. Integer part: for every real there is exactly one integer with bounds their number by , so all stacks together have volume at most .
Summing over the finitely many domain cells gives total covering volume at most a rectangle-dependent constant times . Choose and then to make this below .
This finite cube cover proves content zero in the sense of Measure zero and content zero in by countable and finite cube covers.
Depends on
Measure zero and content zero in by countable and finite cube covers
Grid partitions of a rectangle in , their cells, refinements and mesh
Axis-parallel rectangles in and their volume
Heine-Borel in : with the Euclidean metric a subset of is compact if and only if it is closed and bounded, and the proof by bisection uses no choice principle; the same holds on the real line
Heine-Cantor: a continuous map from a compact metric space to any metric space is uniformly continuous
Continuity of a map between metric spaces, at a point and globally, in the - form
Each is a norm on , and the induced metrics are exactly , and of the published metric-spaces page
Integer part: for every real there is exactly one integer with
The canonical natural of a field
Laws of finite sums and finite products