Alphabeta Math
LemmaStatement: Literature-sourcedProof: AI-generatedPipeline-generatedjudge pass (gpt-6-luna)
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.

Mean value theorem on a closed real interval

Statement

Let f:[a,b]→R be continuous on [a,b] and differentiable on (a,b), with a<b. Then there is c∈(a,b) such that

f(b)−f(a)=f′(c)(b−a).

Facts & Assumptions

Given: A field satisfying Dedekind-complete ordered real field, real endpoints a<b, and f:[a,b]→R continuous on [a,b] and differentiable on (a,b) as defined in Continuity and derivative on a real interval.

[F1]

Continuity and derivative on a real interval: continuity is the relative epsilon-delta condition; differentiability is existence of the finite two-sided difference-quotient limit.

[L1]

Rolle's theorem from attained extrema: a continuous function on [a,b] differentiable on (a,b) with equal endpoint values has an interior point with derivative zero.

Proof

1.1givenF1L1construct

Let m=(f(b)−f(a))/(b−a) and define g(t)=f(t)−f(a)−m(t−a). The function g is continuous on [a,b] and differentiable on (a,b) by [F1], and g(a)=g(b)=0. Applying [L1] gives c∈(a,b) with g′(c)=0.

2.1step 1.1algebra∎

Differentiating the displayed affine expression gives g′(c)=f′(c)−m=0. Thus f′(c)=(f(b)−f(a))/(b−a); multiplying by b−a>0 proves the identity.

Depends on

Used by

Dependency tree · two levels

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Sources