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.
A boundary score cone differs from its tangent space
Example
Assume the general DQM density-version convention uses AC and the mean-zero Hilbert-space convention uses Countable Choice; the two-point densities below are explicit, so this proof itself makes no choice. Let with all subsets measurable and let for . At the boundary law , consider allowed one-sided paths with , , and an existing right derivative at zero. Their DQM score set is the cone , while its closed linear tangent space is all of . Thus the score set and its linear tangent space are distinct.
Facts & Assumptions
Given: AC and Countable Choice, the restricted model on the two-point sample space, based at .
AC is the axiom that every family of nonempty sets has a choice function (The Axiom of Choice).
Countable Choice gives a choice function for every countable family of nonempty sets (The Axiom of Countable Choice ()).
A one-sided DQM score satisfies (A dominated differentiable-in-quadratic-mean submodel).
Such a score has mean zero and is unique -almost surely (A DQM score has mean zero and is unique).
The tangent set records the scores of allowed paths; the tangent space is the closure of their linear span (Tangent set of a statistical model at a law, Closed tangent space).
The full power set is a sigma-algebra, and a measurable space is a set with a specified sigma-algebra (Sigma-algebras, Measurable spaces and measurable sets).
Counting measure assigns a finite set its cardinality; on this two-point sample space its total mass is two (Counting measure on an arbitrary set).
Counting measure is a measure, and a finite measure is sigma-finite (Counting measure is a measure, Finite, sigma-finite, and semifinite measures).
For every , the square-root function is differentiable with derivative (Continuity and derivatives of positive-base real powers).
Under Countable Choice, is closed in (The mean-zero L² space is a Hilbert space).
Verification
Every subset of and its complement lie in the full power set, and every countable union of such subsets is still a subset; thus the power set is a sigma-algebra by [F4], and with this sigma-algebra the sample set is a measurable space by [F4]. Counting measure on the two-point set is a measure of total mass two by [F5, F6], hence sigma-finite by the constant sequence of covers ; its only null set is empty. For every , the masses and are nonnegative and sum to one, so is a probability measure dominated by counting measure. At both masses are , so .
If a one-sided DQM path has score , [F1] on each atom gives . Squaring each expansion yields .
Conversely, for each , take for sufficiently small . Then , and [F7] at gives on each atom. The two-coordinate counting-measure remainder is , so this path has score . Its densities are explicit, so [A1] requires no selection in this construction. Thus every vector on the nonnegative ray is an allowed score.
Subtract the two mass expansions from step 2.1. Since , we get . By [F2], , so this limit equals . The constraints and force the limit to be nonnegative, and ; hence every score is with .
The real span of is , and every mean-zero function on the equiprobable two-point space has values , so this span is . This space is closed in by [F8], hence its closure—and therefore the tangent space by [F3]—is . It strictly contains the non-linear score cone because is in the cone but is not.
Depends on
- A dominated differentiable-in-quadratic-mean submodel
- A DQM score has mean zero and is unique
- Mean-zero square-integrable functions
- The Axiom of Choice
- The Axiom of Countable Choice ($\mathrm{AC}_\omega$)
- Tangent set of a statistical model at a law
- Closed tangent space
- Measurable spaces and measurable sets
- Probability measures and probability spaces
- Sigma-algebras
- Counting measure on an arbitrary set
- Counting measure is a measure
- Finite, sigma-finite, and semifinite measures
- Continuity and derivatives of positive-base real powers
- The mean-zero L² space is a Hilbert space
Used by
Nothing in the library uses this result yet.
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