OreAlgebraLean verification blueprint

3 Section 3, Id. 2: \(q\)-Stirling of the first kind (corrected)

Theorem 3 Id. 2, corrected convention
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For all \(q : \mathbb {Q}\):

\[ F(m,n) \; =\; \sum _k (-1)^{n-k}\binom {k}{m}\, S_1^q(n,k)\, q^{\, n-k} \; =\; (-1)^{n-m} S_1^q(n+1,m+1), \]

with the unweighted \(S_1^q\) (\(S_1^q(n+1,k+1)=S_1^q(n,k)-[n]_q S_1^q(n,k+1)\)), satisfying \(F(m+1,n+1)=F(m,n)+[n+1]_q\, F(m+1,n)\).

Note: the printed \(q^{-k}\) summand with the \(S_1\) read *unweighted* does not satisfy the printed closed form (the restricted search in cas/check_id2_convention.py has exactly one hit — the convention above). The corrected certificate is \(g(m,n,k)=(-1)^{n-k}q^{\, n-k+1}\binom {k}{m+1}S_1^q(n,k-1)\).

Remark 4 Id. 2 Katriel reading: printed statement valid as printed
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The printed Id. 2 of the paper states \(F(m,n) = \sum _k (-1)^{n-k} \binom {k}{m} S_1^K(n,k)\, q^{-k} = (-1)^{n-m} S_1^K(n+1,m+1)\) for \(q \ne 0\), with the Katriel first kind \(S_1^K\) (recurrence \(S_1^K(n+1,k+1) = q^{-n}(S_1^K(n,k) - [n]_q S_1^K(n,k+1))\), plain binomial \(\binom {k}{m}\)). Under the rescaling \(S_1^K(n,k) = q^{-\binom n2} S_1^q(n,k)\) the printed summand is termwise the \(q^{-n(n+1)/2}\)-conjugation of the verified summand above (the column weight depends on \(n\) only): \(q^{-k} S_1^K(n,k) = q^{-n(n+1)/2}\cdot q^{n-k} S_1^q(n,k)\). Conjugation by column weights depending on \(n\) alone maps the verified identity to the printed identity and transports the recurrence coefficients, so the printed identity AND the paper’s printed 3-term recurrence \(-(q-1)q^{n+1}F(m+1,n+1) + (q-1)F(m,n) + (q^{n+1}-1)F(m+1,n) = 0\) hold as printed. This is verified with exact rationals over a q-grid including \(-1\) by cas/check_id2_katriel.py. The printed certificate includes \((-1)^{n-k}\) and also passes the pointwise and boundary checks under this weight. The earlier negative audit omitted that sign and used the wrong operator.

Lean scope: the printed recurrence, closed form, interior certificate, and weighted boundary layer are proved. Introducing the Carlitz row weight \(\hat S_1(n,k) := q^{-\binom n2} S_1^q(n,k)\) (Lean id2Shat1), the printed weighted formulas below are transported from the verified unweighted layer on the stated domains, with column weight \(t(n) := q^{-\binom {n+1}{2}} = q^{-n(n+1)/2}\):

  • Weighted summand and sum: \(\hat F(m,n) = t(n)\, F(m,n)\) termwise (id2_summand_conj, id2_sum_conj).

  • Printed operator: the printed 3-term operator equals \(-(q-1)\, t(n)\) times the verified unweighted operator, with no range restriction (id2_op_series_conj).

  • Printed certificate: the printed \(g(m,n,k) = (-1)^{n-k}\frac{(m-k)(q-1)q^{\, 1-k}}{m+1}\binom {k}{m}\hat S_1(n,k-1)\) equals \(-(q-1)\, t(n)\, g_0(m,n,k)\) for all \(k \le n\), where \(g_0\) is the corrected unweighted certificate above; this uses the absorption identity \((m-k)\binom {k}{m}/(m+1) = -\binom {k}{m+1}\) (id2_cert_conj).

  • Printed pointwise identity: the printed operator telescodes against the printed certificate pointwise on \(k+1 \le n\), \(L\hat(f)(m,n,k) = \hat g(m,n,k{+}1) - \hat g(m,n,k)\) (id2_pointwise_certificate_weighted).

  • Printed closed form: transporting the verified identity (section3Id2_identity) through the conjugation gives the printed right-hand side \(\hat F(m,n) = (-1)^{n-m}\, \hat S_1(n+1,m+1)\) for all \(m, n\) and \(q \ne 0\), with the level-exponent reconciliation \(q^{-n(n+1)/2} = q^{-\binom {n+1}{2}}\) handled termwise ().

  • The printed recurrence \(\widehat{L\hat F}(m,n) = -(q-1)\, t(n)\cdot 0 = 0\) follows from section3Id2_weighted_identity.

  • Weighted boundary layer (proved). The printed weighted transport of the boundary argument is fully formalized: (bottom endpoint vanishing), (upper sentinel shift \(\hat g(m,n,n{+}1) = (q-1)q^{n+1}\, \hat w(m{+}1,n{+}1,n{+}1)\)), (top endpoint pointwise case), (shifted-range reconciliation with printed sentinels), (weighted telescoping over \(\mathrm{Icc}(m{+}1)\, n\)), and (the weighted boundary identity: \(\hat L(n) + (-(q-1)q^{n+1}\hat w(m{+}1,n{+}1,n{+}1) + (q-1)\hat w(m,n,m)) + (\hat g(n) - \hat g(m{+}1)) = 0\)).