Alphabeta Math
LemmaStatement: Literature-sourcedProof: AI-generatedPipeline-generatedprecheck pass
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.

Leading composite Simpson error coefficient

Statement

Let a<b, let k≥1 be an integer, set nk=2k and hk=(b−a)/nk, and let Qk=QS(f;a,b,nk) for f∈C4([a,b]). With I=∫abf(x) dx, one has I−Qk=−hk4180∫abf(4)(x) dx+o(hk4)(k→∞). Here rk=o(hk4) means rk/hk4→0 along this sequence. The integral is the Riemann integral.

Facts & Assumptions

Given: A real interval [a,b] with a<b, f∈C4([a,b]), and the composite Simpson values on the grids with nk=2k subintervals.

[F1]

Peano kernel identity for one Simpson panel: on a panel [α,β] of length L, the Simpson kernel has the two quartic pieces displayed in its Statement; they agree at the midpoint, satisfy K≤0, and have ∫αβ∣K∣=L5/2880. The panel error is ∫αβK(x)f(4)(x) dx.

[F2]

Higher derivatives and the classes Ck and C∞: f∈C4([a,b]) means f and its derivatives through order four are continuous on the closed interval, in particular both f and f(4) are continuous.

[F3]

Heine-Cantor: a continuous map from a compact metric space to any metric space is uniformly continuous: a continuous real function on a compact metric space is uniformly continuous.

[F5]

Every continuous function on a closed nondegenerate rectangle in Rm is Riemann integrable: a continuous real function on a closed nondegenerate interval is Riemann integrable.

[F6]

For a<c<b: f is integrable on [a,b] if and only if it is integrable on [a,c] and on [c,b], and then ∫abf=∫acf+∫cbf; with the oriented form for arbitrary a,b,c: for Riemann-integrable f on [a,b] and a<c<b, the restrictions to [a,c] and [c,b] are integrable and ∫abf=∫acf+∫cbf; iterating this two-piece identity gives additivity over any finite adjacent partition.

[F10]

Composite Simpson rule on an even uniform grid: for even n≥2, QS is the sum of the one-block Simpson values on the adjacent panels [x2j,x2j+2], 0≤j<n/2.

[F11]

Every complete ordered field is Archimedean: for every real R there is a natural number N≥1 with R<N.

[F12]

Bernoulli's inequality (1+x)n≥1+nx: if x≥−1 and k∈N, then (1+x)k≥1+kx.

Proof

1.1givenF11F12choosealgebra

Let δ>0 and put R=(b−a)/δ. By [F11] choose N≥1 with R<N. For every k≥N, [F12] with x=1 gives 2k≥1+k≥1+N>R, so hk=(b−a)/2k<δ. Since δ>0 was arbitrary, hk→0.

1.2givenF1F2F3F4F5F7F9algebra

Put g=f(4). By [F2] and [F5], both f and g are integrable. By [F3]–[F4], g is uniformly continuous on the compact interval. The two formulas for Kj in [F1] agree at their shared midpoint, so Kj is continuous; [F9] makes Kj(g−g(cj)) continuous and [F5] makes it integrable. Fix ε>0; choose δ>0 so that ∣g(x)−g(y)∣<ε whenever x,y∈[a,b] and ∣x−y∣<δ. For hk<δ, write each Simpson block as Pj=[cj−hk,cj+hk] with midpoint cj. By [F1] and linearity, its error minus −((2hk)5/2880)g(cj) is ∫PjKj(x)(g(x)−g(cj)) dx. Since Kj≤0 and ∣g(x)−g(cj)∣<ε, [F7] bounds the absolute value of this difference by ε(2hk)5/2880.

2.1step 1.1step 1.2

The δ chosen in step 1.2 is positive, so step 1.1 gives an index after which hk<δ; hence the panel estimate of step 1.2 holds for all sufficiently large k.

3.1givenF5F6F7F8F10step 1.2step 2.1algebra

There are nk/2=(b−a)/(2hk) blocks. By [F10], Qk is the sum of their one-block Simpson values; repeated application of additivity [F6] sums their integrals to I. Hence their local errors sum to I−Qk. If Jk=−((2hk)5/2880)∑jg(cj), step 1.2 gives ∣(I−Qk)−Jk∣≤(b−a)hk4ε/180. Also, on each block the uniform-continuity bound gives g(cj)−ε≤g(x)≤g(cj)+ε. By [F7] and [F8], integrating these constant bounds gives 2hk(g(cj)±ε), so ∣∫Pjg−2hkg(cj)∣≤2hkε. Repeated additivity [F6] then yields ∣2hk∑jg(cj)−∫abg∣≤(b−a)ε.

4.1givenstep 3.1algebra∎

Since Jk/hk4=−(2hk∑jg(cj))/180, step 3.1 shows that ∣(I−Qk)/hk4+(1/180)∫abg∣≤(b−a)ε/90 for all sufficiently large k. As ε>0 was arbitrary, the displayed limit follows.

Depends on

Used by

Dependency tree · two levels

82 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