Analogue of a Fock-type integral arising from electromagnetism and its applications in number theory
Pith reviewed 2026-05-25 01:03 UTC · model grok-4.3
The pith
A kernel mixing Bessel functions J, K and Y produces an integral identity that, combined with Voronoi summation, transforms series of I and K products into hypergeometric expressions.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We derive an analogous integral identity in which the integrand kernel is a linear combination of J_s(ξ), K_s(ξ) and Y_s(ξ) instead of the single function J_s(ξ) appearing in Koshliakov's generalization of Fock's integral. When this identity is substituted into the Voronoi summation formula, it yields a transformation that equates sums of products I_λ(ξ)K_λ(ξ) to series or closed forms involving the Gaussian hypergeometric function _2F1. Applications of the transformation include a corrected version of the first identity on page 336 of Ramanujan's Lost Notebook.
What carries the argument
The mixed kernel formed by the linear combination of J_s(ξ), K_s(ξ) and Y_s(ξ) that replaces the single J_s(ξ) term and makes the integral identity compatible with Voronoi summation.
If this is right
- The transformation equates infinite series of I_λ(ξ)K_λ(ξ) products to expressions containing the Gaussian hypergeometric function.
- Several explicit evaluations of such series follow by specializing the transformation.
- A corrected form of the identity on page 336 of Ramanujan's Lost Notebook is obtained as one application.
- The same kernel identity can be reused with other summation formulas whenever the resulting integral converges.
Where Pith is reading between the lines
- The same kernel construction may be tested with other classical summation formulas such as Poisson or Abel summation to produce further transformations.
- The corrected Ramanujan identity could be checked against independent evaluations obtained from modular-form methods or q-series identities.
- If the kernel extends to non-integer orders or complex parameters, the transformation might generate new identities for series appearing in partition theory.
Load-bearing premise
The newly constructed kernel of J_s, K_s and Y_s yields a convergent integral identity that remains valid when inserted into the Voronoi summation formula for the parameter ranges and series considered in the applications.
What would settle it
Numerical agreement, to high precision, between both sides of the derived transformation for concrete admissible values of λ and ξ, or direct verification that the corrected Ramanujan identity on page 336 holds for the stated parameters.
read the original abstract
Closed-form evaluations of certain integrals of $J_{0}(\xi)$, the Bessel function of the first kind, have been crucial in the studies on the electromagnetic field of alternating current in a circuit with two groundings, as can be seen from the works of Fock and Bursian, Schermann etc. Koshliakov's generalization of one such integral, which contains $J_s(\xi)$ in the integrand, encompasses several important integrals in the literature including Sonine's integral. Here we derive an analogous integral identity where $J_{s}(\xi)$ is replaced by a kernel consisting of a combination of $J_{s}(\xi)$, $K_{s}(\xi)$ and $Y_{s}(\xi)$ that is of utmost importance in number theory. Using this identity and the Vorono\"{\dotlessi} summation formula, we derive a general transformation relating infinite series of products of Bessel functions $I_{\lambda}(\xi)$ and $K_{\lambda}(\xi)$ with those involving the Gaussian hypergeometric function. As applications of this transformation, several important results are derived, including what we believe to be a corrected version of the first identity found on page $336$ of Ramanujan's Lost Notebook.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper derives an analogue of Koshliakov's generalization of Fock-type integrals, replacing the J_s(ξ) integrand with a kernel combining J_s(ξ), K_s(ξ) and Y_s(ξ). It then invokes the Voronoï summation formula to obtain a general transformation relating series of products I_λ(ξ)K_λ(ξ) to expressions involving the Gaussian hypergeometric function, and applies the transformation to produce several identities, including a claimed correction to the first identity on p. 336 of Ramanujan's Lost Notebook.
Significance. If the integral identity and its substitution into Voronoï are rigorously justified, the work would supply a new integral-transform tool for evaluating arithmetic series involving products of modified Bessel functions, extending techniques already used for modular-form coefficients and potentially yielding verifiable corrections to entries in Ramanujan's notebooks.
major comments (2)
- [integral identity derivation] The derivation of the integral identity with the combined J_s/K_s/Y_s kernel (abstract and the section presenting the identity) asserts convergence but supplies no explicit majorant, dominated-convergence argument, or growth estimates that would justify absolute convergence and interchange with the Voronoï sum for the ranges of Re(s), λ and ξ appearing in the subsequent applications to I_λ K_λ series.
- [applications to series transformations] The applications that invoke the new transformation inside Voronoï (including the claimed correction to Ramanujan's p. 336 identity) presuppose that the kernel integral remains valid under the summation conditions of Voronoï; no separate verification or reference to standard estimates for the oscillatory-plus-exponential kernel is given, rendering the correction claim dependent on an unproven interchange.
minor comments (2)
- Notation for the combined kernel is introduced without an explicit displayed equation number, making cross-references in the applications section difficult to follow.
- The abstract states that the identity 'encompasses several important integrals' but does not list the recovered classical cases (Sonine, etc.) with equation numbers.
Simulated Author's Rebuttal
We thank the referee for the careful reading and constructive comments. We address the major concerns point by point below.
read point-by-point responses
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Referee: The derivation of the integral identity with the combined J_s/K_s/Y_s kernel (abstract and the section presenting the identity) asserts convergence but supplies no explicit majorant, dominated-convergence argument, or growth estimates that would justify absolute convergence and interchange with the Voronoï sum for the ranges of Re(s), λ and ξ appearing in the subsequent applications to I_λ K_λ series.
Authors: We agree that the manuscript would benefit from more explicit convergence arguments. In the revised version, we will supply growth estimates for the kernel functions in the relevant ranges of Re(s), λ and ξ, together with a dominated-convergence justification for the integral representation and its interchange with the Voronoï sum. revision: yes
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Referee: The applications that invoke the new transformation inside Voronoï (including the claimed correction to Ramanujan's p. 336 identity) presuppose that the kernel integral remains valid under the summation conditions of Voronoï; no separate verification or reference to standard estimates for the oscillatory-plus-exponential kernel is given, rendering the correction claim dependent on an unproven interchange.
Authors: We acknowledge that a dedicated verification of the interchange under the summation conditions of Voronoï is required. In revision we will add a subsection providing asymptotic estimates for the oscillatory-plus-exponential kernel, drawing on standard Bessel-function bounds, to justify the interchange for the series under consideration and thereby support the claimed correction to the Ramanujan identity. revision: yes
Circularity Check
No circularity: derivation is self-contained via external Voronoï formula and novel kernel identity
full rationale
The paper constructs a new integral identity by direct analogy to Koshliakov's known generalization of Fock-type integrals, replacing the J_s integrand with an explicit linear combination of J_s, K_s and Y_s; this step is presented as an independent derivation rather than a fit or renaming. The subsequent transformation is obtained by substituting the identity into the standard Voronoï summation formula (an externally established arithmetic tool with no author overlap cited as load-bearing). No equation reduces to a self-defined quantity, no parameter is fitted then relabeled as prediction, and no uniqueness theorem or ansatz is smuggled via self-citation. The Ramanujan correction and hypergeometric series relations follow from these steps without circular reduction. The derivation chain therefore remains independent of its own outputs.
Axiom & Free-Parameter Ledger
axioms (2)
- standard math Standard analytic properties and integral representations of Bessel functions J, Y, K, I hold in the relevant parameter ranges.
- domain assumption Voronoï summation formula applies directly to the series of Bessel products under consideration.
Reference graph
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