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 finite double-exponential trapezoid has separate strip and tail errors
Statement
Use one of the modes of Finite truncated tanh–sinh, exp–sinh, and sinh–sinh trapezoid rules and let be its transformed real integrand. Suppose has an extension satisfying all hypotheses of An analytic-strip error bound for the infinite trapezoid sum for some , with horizontal integrals . Also suppose for , where , and . If is the target improper integral and is the finite sum in the algorithm, then it is absolutely convergent as an improper integral and The strip and tail hypotheses are separate assumptions; integrability alone implies neither estimate.
Facts & Assumptions
Given: A mode and transformed function from Finite truncated tanh–sinh, exp–sinh, and sinh–sinh trapezoid rules, its target , an analytic extension satisfying the strip hypotheses, and a double-exponential real-tail envelope with the stated cutoff conditions.
Finite truncated tanh–sinh, exp–sinh, and sinh–sinh trapezoid rules: the output is .
The double-exponential maps and their change-of-variable identities: if is absolutely integrable as an improper Riemann integral, the target exists absolutely and equals .
An analytic-strip error bound for the infinite trapezoid sum: under the closed-substrip exponential bound and analyticity hypotheses, and the infinite sum is absolutely convergent.
A double-exponential envelope bounds the omitted trapezoid tails: the continuous and sampled omitted tails each have the stated one-sided envelope bound.
A continuous function on is Riemann integrable, by Heine-Cantor and Riemann's criterion: a continuous real function on a compact interval is Riemann integrable there.
Proof
Put . The envelope holds for , and together with gives . Thus [F4] makes the two tails outside absolutely integrable. Set . The continuous function is Riemann integrable on by [F5], and this interval contains both cutoffs, so is absolutely integrable on as an improper Riemann integral. Now [F2] identifies .
By [F3], is absolutely convergent. Splitting its terms into and the two omitted tails is therefore valid.
Add and subtract the infinite trapezoid sum. The triangle inequality bounds the target-to-finite-sum error by the target-to-infinite-sum error plus the absolute omitted sample sum.
Apply [F3] to the first term in step 2.1 and the sampled-tail estimate [F4], with cutoff from step 1.1, to the second. Their sum is the displayed bound.
Depends on
- Finite truncated tanh–sinh, exp–sinh, and sinh–sinh trapezoid rules
- The double-exponential maps and their change-of-variable identities
- An analytic-strip error bound for the infinite trapezoid sum
- A double-exponential envelope bounds the omitted trapezoid tails
- A continuous function on $[a,b]$ is Riemann integrable, by Heine-Cantor and Riemann's criterion
Used by
Cited to discharge well-definedness by Finite truncated tanh–sinh, exp–sinh, and sinh–sinh trapezoid rules.
Dependency tree · two levels
55 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
- Lloyd N. Trefethen and J. A. C. Weideman, The Exponentially Convergent Trapezoidal Rule, SIAM Review 56(3), 2014 (standard reference, not scraped)