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A multiscale Abel kernel and application in viscoelastic problem

T0 review · 2 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash

Pith's one-line read The paper establishes that the variable-exponent Abel kernel $k(t)=t^{\alpha(t)-1}/\Gamma(\alpha(t))$ with $\alpha(0)=1$ models a single relaxation process that is quasi-exponential at short times and power-law at long times, and proves a…

desk verdict A solid second-order scheme for a variable-exponent Abel kernel PIDE, with a real but repairable regularity gap in the temporal error proof. read the letter →

arxiv 2411.16078 v1 pith:BPHENEBY submitted 2024-11-25 math.NA cs.NA

classification math.NAcs.NA MSC 45K0565M1265M60
keywords variable-exponentAbelkernelmultiscalecrossoverdynamicsviscoelasticityintegro-differentialequationCrank-NicolsonmethodGalerkinfiniteelementexponentiallyweightedenergy
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper introduces the variable-exponent Abel kernel $k(t)=t^{\alpha(t)-1}/\Gamma(\alpha(t))$ and argues that when $\alpha(0)=1$ this single kernel produces a multiscale relaxation: quasi-exponential at short times and power-law decay at long times, with the crossover time adjustable through the exponent $\alpha(t)$. It applies this kernel to a parabolic integro-differential equation for viscoelastic vibration and derives well-posedness and high-order regularity estimates for its solutions. The main numerical claim is a fully discrete Crank-Nicolson Galerkin scheme that is second order in time and space, $\|u^m-U_h^m\|\le Q(\tau^2+h^2)$, despite the kernel being neither positive nor monotone; the proof uses an exponentially weighted energy argument. The underlying aim is to turn a mathematically awkward variable-order memory kernel into a practical, provably accurate model for materials whose properties change under load.

What carries the argument

The machinery that carries the argument is the linearly interpolated Crank-Nicolson discretization of the variable-exponent convolution $I^{(\alpha(t))}\phi(t)=\int_0^t (t-s)^{\alpha(t-s)-1}/\Gamma(\alpha(t-s))\phi(s)\,ds$, combined with an exponentially weighted energy framework. The paper rescales all discrete unknowns by $\hat V^n=e^{-\lambda t_n}V^n$ and uses the modified difference quotient $\delta^\lambda_t \hat V^n=(\hat V^n-e^{-\lambda\tau}\hat V^{n-1})/\tau$, then tests against the weighted average $\Lambda_\lambda(\hat V^n)$; choosing $\lambda$ large and $\tau$ small makes the awkward non-positive, non-monotone quadrature coefficients harmless through estimates like $Q\zeta(\tau^{\alpha_*}+\lambda^{-\alpha_*})\le \mu$. The regularity side uses Laplace-representation and semigroup smoothing estimates to control $\partial_t^2\Delta u$ and $\partial_t^3 u$, which feed the interpolation remainder and Taylor terms of the error equation.

What would settle it

Take data satisfying Theorem 3.5 but with $\partial_t^2\Delta u$ having an $L^p$-integrable yet unbounded singularity at $t=0$ (for example behaving like $t^{-1/p}$), run the fully discrete scheme with decreasing $\tau$ and fixed small $h$, and check whether $\|u^m-U_h^m\|/\tau^2$ stays bounded. If it grows like $\tau^{-\varepsilon}$ or $\log(1/\tau)$, the regularity hypotheses in the theorem are insufficient for the stated second-order bound.

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Extended reading notes

Core claim

On the paper's own terms, the central discovery is that the kernel in (1.1) is a multiscale object rather than a technical nuisance: with $\alpha(0)=1$ it eliminates the initial singularity of constant-exponent Abel kernels and still reproduces their long-time power-law tail, so it can represent crossover dynamics that a single power law cannot. The paper then proves that the initial-boundary-value problem (1.3)-(1.5) with this kernel is well posed and that its solution enjoys enough regularity to support a second-order time discretization. The load-bearing theorem is Theorem 4.3: the fully discrete Crank-Nicolson Galerkin scheme (4.30) is stable and satisfies $\|u^m-U_h^m\|\le Q(\tau^2+h^2)$ under the regularity hypotheses of Theorem 3.5. Numerical experiments with $\alpha(t)=1-\frac45 t$ show second-order rates in both time and space and display the predicted crossover from the quasi-exponential short-time solution to the power-law long-time solution.

Load-bearing premise

The load-bearing premise is that, under the regularity stated in Theorem 3.5, the linear-interpolation remainder for the convolution term is pointwise $O(\tau^2)$ on every time interval, which requires $\partial_t^2\Delta u$ to be uniformly bounded in $L^2$ at the mesh-dependent evaluation point; Theorem 3.5 delivers only an $L^p$-in-time bound for finite $p$, so if that uniformity fails the clean quadratic error estimate is not justified.

Editorial extensions

If this is right

  • The fully discrete scheme (4.30) is a rigorously second-order method for the variable-exponent viscoelastic PIDE, improving the first-order scheme of [40] and matching the convergence rates observed numerically.
  • The error bound separates temporal and spatial contributions, so time step and mesh size can be refined independently while retaining $O(\tau^2+h^2)$ accuracy.
  • The exponentially weighted energy framework handles kernels that are neither positive nor monotone, so the proof strategy can be reused for other nonlocal memory terms with oscillatory coefficients.
  • With $\alpha(0)=1$, the model predicts a finite initial response rate instead of the singularity seen for constant-exponent kernels, which is relevant to startup behavior in vibration problems.
  • The numerical experiments show a crossover from short-time quasi-exponential response to long-time power-law response, giving a concrete signature of the multiscale kernel in mechanical vibration.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A natural extension not pursued in the paper is to derive an explicit relation between the crossover time and the decay rate of $\alpha(t)$; such a relation could let one estimate the exponent dynamics from measured relaxation curves.
  • The proof uses only size and logarithmic-derivative bounds on $k$, so the same quadrature-weighting framework is likely to transfer to tempered or distributed-order Abel-type kernels.
  • A conservative reading of the error proof suggests the clean $\tau^2$ rate rests on a uniform-in-time bound for $\partial_t^2\Delta u$, stronger than the $L^p$-in-time regularity proved in Theorem 3.5; constructing a borderline example would show whether the stated hypotheses are minimal.
  • For viscoelastic testing, the model implies a two-regime amplitude envelope in a single experiment, a falsifiable distinction from constant-exponent viscoelastic models.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. This paper introduces the variable-exponent Abel kernel k(t)=t^{α(t)-1}/Γ(α(t)) with α(0)=1 as a multiscale kernel, and applies it to the parabolic integro-differential equation (1.3)-(1.5) that models viscoelastic vibration. The authors prove well-posedness and regularity results (Theorems 3.2, 3.4, and 3.5), propose a Crank-Nicolson time discretization combined with linear-interpolation quadrature for the memory term and a piecewise-linear finite element spatial discretization (scheme (4.30)), and analyze the scheme with an exponentially weighted energy argument. The main theoretical claim is Theorem 4.3: under the regularity hypotheses of Theorem 3.5, the fully discrete solution satisfies ||u^m - U_h^m|| ≤ Q(τ² + h²). Numerical experiments in Section 5 confirm second-order temporal and spatial convergence and illustrate a crossover from short-time quasi-exponential to long-time power-law behavior.

Significance. The main theoretical contribution, if fully justified, is a rigorous second-order-in-time convergence proof for a PIDE with a variable-exponent Abel kernel, improving the first-order scheme of [40]. The exponentially weighted energy framework for the non-positive and non-monotone kernel is a useful extension of existing techniques, and the convergence tables in Table 5.1 provide clean numerical support for the claimed O(τ² + h²) accuracy. The paper is transparent about its reliance on [40] for several intermediate estimates, and the crossover dynamics in Fig. 5.2 is a nice qualitative illustration of the multiscale kernel. However, the proof of the temporal quadrature error contains a regularity gap that is load-bearing for Theorem 4.3; until that gap is repaired, the O(τ²) part of the central claim is not fully proven.

major comments (2)
  1. [§4.2, Eq. (4.28)] The bound (4.28) for the quadrature error R_2^n is not justified by the stated regularity assumptions. The derivation writes the linear-interpolation remainder of Δu as (1/2) ∂_t^2 Δu(ξ_j)(s-t_j)(s-t_{j-1}) with ξ_j∈(t_{j-1},t_j) and then bounds ||∂_t^2 Δu(ξ_j)|| by a generic constant Q. This requires a pointwise, uniform-in-time L²-space bound for ∂_t^2 Δu. Theorem 3.5, however, only yields ∂_t^2 u ∈ L^p(0,T; ˇH²), i.e. ∂_t^2 Δu ∈ L^p(0,T; L²) for finite p, which does not imply pointwise values of the second time derivative. The gap is repairable: replacing the pointwise evaluation by a Peano-kernel representation of the interpolation error and using Young's convolution inequality with the kernel t^{α_*-1} should recover O(τ²) from the available L^p regularity, but the argument must be written out.
  2. [§4.3, proof of Theorem 4.3] The proof of the spatial error estimate (4.34) is only sketched and omits a load-bearing estimate. In the error equation (4.32), the right-hand side contains δ_t^λ η^n, the time difference of the Ritz projection error. To obtain the h² term, one must estimate τ Σ_{n=1}^m ||δ_t^λ η^n||² (or the corresponding inner-product term) by Q h^4 ||∂_t u||_{L²(ˇH²)}², using the representation δ_t η^n = τ^{-1} ∫_{t_{n-1}}^{t_n} ∂_t η(s) ds. The sentence 'use ||η^m|| ≤ Q h²||u||_{L∞(H²)} and combine Theorem 4.2' does not supply this bound; only the pointwise-in-time Ritz error is bounded there, not its time difference. This is a standard and presumably correct estimate, but it needs to be displayed for the proof to be complete.
minor comments (5)
  1. [§1.1, bullet list] The word 'muitiscale' in the first bullet should be 'multiscale'.
  2. [§4.2, proof of Theorem 4.2] The step from (4.22) to (4.26) is quite compressed. In particular, the 'selecting m*' argument should explicitly handle the case ||ρ^{m*}||=0 and should state which constants absorb the factors e^{-λt_n} and the discrete Gronwall step.
  3. [§4.3, Theorem 4.3] Theorem 4.3 is stated as a stability result but also contains the error estimate (4.34); separating these two statements would make the logical structure clearer.
  4. [§3, Lemmas 3.3 and 3.4] The paper relies on [40] for well-posedness, Lemma 3.3, and Theorem 3.4 without proof. Since these results are central to the regularity chain, a short paragraph at the beginning of Section 3 indicating exactly which statements are proved here and which are imported from [40] would improve readability.
  5. [§1.1, Eq. (1.2)] The classification of k_0(t)=e^{α'(0)t ln t} as 'quasi-exponential' is somewhat imprecise, since the exponent is proportional to t ln t rather than t; a brief clarification of the intended meaning would avoid confusion.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: the Crank–Nicolson Galerkin error estimate is independently constructed; the L^p-to-L^∞ regularity gap at (4.28) is a proof gap, not a circular reduction.

full rationale

No circular step is present. The fully discrete scheme (4.30) and the error bound (4.34) are built from the Crank–Nicolson average and the linear-interpolation quadrature (4.3)–(4.7); the error equation (4.32) is obtained by direct subtraction of (4.30) from the consistency relation (4.8), so no discrete solution or fitted parameter is fed back into the truncation analysis. The bounds on the consistency terms R_n^1 and R_n^2 in (4.27)–(4.28) use only regularity of the exact solution, not the target error, so no “prediction” is forced by construction. The paper explicitly states that well-posedness and lower-order regularity follow the authors’ prior work [40] and omits those proofs; this is a self-citation chain, but [40] is a published, externally checkable set of theorems with stated assumptions that do not include the second-order convergence result, so it is real evidence rather than a tautology. The crossover discussion in Fig. 1.1 is an asymptotic comparison for the chosen α(t), not a first-principles prediction. The only serious issue is non-circular: (4.28) evaluates ‖∂_t^2Δu(ξ_j)‖ pointwise in time, whereas Theorem 3.5 supplies only ∂_t^2u ∈ L^p(H^2) for finite p; that is a missing regularity argument in the O(τ^2) proof, not an equality of input and output. Verdict: no circularity.

Assumptions & free parameters 0 free parameters · 6 assumptions · 0 invented entities

The central proof imports several core estimates and well-posedness results from the authors' own [40] and assumes smoothness of alpha, f, and u0. No parameters are fitted to data; the only adjustable quantities in examples are illustrative choices of alpha(t).

assumptions (6)
  • domain assumption Assumption A(i): 0 < alpha_* <= alpha(t) <= 1, alpha(0)=1, |alpha'(t)| <= Q and |alpha''(t)| <= Q on [0,T].
    Invoked throughout Sections 3 and 4 to control kernel regularity and to remove the initial singularity at t=0; stated before Section 2.2.
  • domain assumption Assumption A(ii): f in L^p(L^2) and Delta u0 in L^2 for some 1 < p < infinity.
    Used for well-posedness and the regularity estimates in Theorems 3.2 and 3.5.
  • domain assumption Higher regularity: alpha in W^{4,infinity}(0,T), u0 in check H^6, f in W^{2,p}(L^2) intersect W^{1,p}(check H^2) intersect L^p(check H^{4+sigma}).
    Assumed in Theorem 3.5 to prove the W^{2,p}(check H^2) and W^{3,p}(L^2) estimates needed for the second-order error analysis.
  • standard math Semigroup and contour integral estimates (2.1) and (2.6) from [2,23].
    Underpins the solution representation (3.2) and the bounds on convolution terms in Theorem 3.5.
  • standard math Kernel derivative bounds |k(t)| <= Q, |k'(t)| <= Q(1+|ln t|), |k''(t)| <= Q t^{-1} from [40, Lemma 3.2].
    Used to bound terms involving k' and k in the regularity and error proofs; imported from the authors' previous paper.
  • standard math Well-posedness and first regularity results of [40, Theorems 3.1 and 4.2] are taken as known.
    The paper states Theorem 3.2 and Lemma 3.3 without proof, saying they follow [40]; these results support the later high-order estimates.

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Cite this review

Pith. "Pith review of A multiscale Abel kernel and application in viscoelastic problem." pith.science (2026). https://pith.science/paper/BPHENEBY

@misc{pith2026241116078,
  author       = {Pith},
  title        = {Pith review of: A multiscale Abel kernel and application in viscoelastic problem},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/BPHENEBY}},
  note         = {Machine review of arXiv:2411.16078}
}
read the original abstract

We consider the variable-exponent Abel kernel and demonstrate its multiscale nature in modeling crossover dynamics from the initial quasi-exponential behavior to long-term power-law behavior. Then we apply this to an integro-differential equation modeling, e.g. mechanical vibration of viscoelastic materials with changing material properties. We apply the Crank-Nicolson method and the linear interpolation quadrature to design a temporal second-order scheme, and develop a framework of exponentially weighted energy argument in error estimate to account for the non-positivity and non-monotonicity of the multiscale kernel. Numerical experiments are carried out to substantiate the theoretical findings and the crossover dynamics of the model.

Figures

Figures reproduced from arXiv: 2411.16078 by the authors.

Figure 1.1
Figure 1.1. Log-log plots of (left) k(t) in (1.1) with α(t) = 0.9 + 0.1e −0.1t and its asymptotics in (1.2) and (right) k(t; a) with α(t; a) = 0.7 + 0.3e−at for different a and the Mittag-Leffler kernel kE(t). It is worth mentioning that similar multiscale features could also be realized by the well-known Mittag–Leffler kernel kE(t) := Eβ,1(−t β ), Eβ,1(z) := X∞ i=0 z i Γ(βi + 1), z ∈ R for some 0 < β < 1. It is demonstrated in… view at source ↗
Figure 1.2
Figure 1.2. Plots of ∂tu(0.5, t) under different α(t). 1.3. Novelty and contribution. For the case α(t) ≡ α¯ for some 0 < α¯ ≤ 1, there exist extensive mathematical analysis results for the PIDE (1.3) [10, 13, 15, 16, 39]. For numerical approximation, different numerical methods have been considered for PIDEs and their variants, such as finite element methods [4, 5, 28], discontinuous Galerkin methods [20, 29], convolution quad… view at source ↗
Figure 5
Figure 5. (right) under the same data and [PITH_FULL_IMAGE:figures/full_fig_p017_5.png] view at source ↗
Figures from the paper (2 more)
Figure 5.1
Figure 5.1. Figure 5.1: Solution curves of u(0.5, t) under different parameters [PITH_FULL_IMAGE:figures/full_fig_p017_5_1.png]
Figure 5.2
Figure 5.2. Figure 5.2: Solution curves of u(5, t) under different kernels. Acknowledgments. This work was partially supported by the National Natural Science Foundation of China (12301555, 12271303), the National Key R&D Program of China (2023YFA1008903), the Taishan Scholars Program of Sh…

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Works this paper leans on

40 extracted references · 40 canonical work pages

  1. [40]

    Zheng, Y

    X. Zheng, Y. Li, W. Qiu, Local modification of subdiffusion by initial Fickian diffusi on: Multi- scale modeling, analysis, and computation , Multiscale Model. Simul., 22 (2024), 1534–1557

  2. [1]

    Adams and J

    R. Adams and J. Fournier, Sobolev Spaces, Elsevier, San D iego, 2003

  3. [2]

    Akrivis, B

    G. Akrivis, B. Li, and C. Lubich, Combining maximal regularity and energy estimates for time discretizations of quasilinear parabolic equations , Math. Comp., 86 (2017), 1527–1552

  4. [3]

    Bonfanti, J

    A. Bonfanti, J. L. Kaplan, G. Charras, A. Kabl, Fractional viscoelastic models for power-law materials, Soft Matter, 16 (2020), 6002–6020

  5. [4]

    J. R. Cannon, Y. Lin, A priori L2 error estimates for finite-element methods for nonlinear diffusion equations with memory , SIAM J. Numer. Anal., 27 (1990), 595–607

  6. [5]

    C. Chen, V. Thom´ ee, L. B. W ahlbin, Finite element approximation of a parabolic integro- differential equation with a weakly singular kernel , Math. Comp., 58 (1992), 587–602

  7. [6]

    S. W. Cheung, E. T. Chung, Y. Efendiev, W. T. Leung, Explicit and energy-conserving con- straint energy minimizing generalized multiscale discont inuous Galerkin method for wave propagation in heterogeneous media , Multiscale Model. Simul., 19 (2021), 1736–1759

  8. [7]

    E. T. Chung, Y. Efendiev, R. L. Gibson, M. Vasilyeva, A generalized multiscale finite element method for elastic wave propagation in fractured media , GEM-Int. J. Geomath., 7 (2016), 163–182. A multiscale power-law kernel and its application 19

Show all 40 references
  1. [8]

    R. Dang, Y. Cui, J. Qu, A. Yang, Y. Chen, Variable fractional modeling and vibration analysis of variable-thickness viscoelastic circular plate , Appl. Math. Model., 110 (2022), 767–778

  2. [9]

    W. Deng, B. Li, W. Tian, and P. Zhang, Boundary problems for the fractional and tempered fractional operators, Multiscale Model. Simul., 16 (2018), 125–149

  3. [10]

    Engler, On the dynamic shear flow problem for viscoelastic liquids , SIAM J

    H. Engler, On the dynamic shear flow problem for viscoelastic liquids , SIAM J. Math. Anal., 18 (1987), 972–990

  4. [11]

    Evans, Partial Differential Equations , Graduate Studies in Mathematics, Graduate Studies in Mathematics, V 19, American Mathematical Society, Rhode Island, 1998

    L. Evans, Partial Differential Equations , Graduate Studies in Mathematics, Graduate Studies in Mathematics, V 19, American Mathematical Society, Rhode Island, 1998

  5. [12]

    W. Fan, X. Hu, and S. Zhu, Numerical reconstruction of a discontinuous diffusive coeffi cient in variable-order time-fractional subdiffusion , J. Sci. Comput., 96 (2023), 13

  6. [13]

    Friedman, M

    A. Friedman, M. Shinbrot, Volterra integral equations in Banach space , Trans. Amer. Math. Soc., 126 (1967), 31–179

  7. [14]

    Z. Hao, W. Cao, G. Lin, A second-order difference scheme for the time fractional sub stantial diffusion equation , J. Comput. Appl. Math., 313 (2017), 54–69

  8. [15]

    M. L. Heard, An abstract parabolic Volterra integrodifferential equati on, SIAM J. Math. Anal., 13 (1982), 81–105

  9. [16]

    M. L. Heard, S. M. Rankin III, A semilinear parabolic Volterra integrodifferential equat ion, J. Differential Equ., 71 (1988), 201–233

  10. [17]

    J. Jeon, N. Leijnse, L. Oddershede, R. Metzler, Anomalous diffusion and power-law relaxation of the time averaged mean squared displacement in worm-like micellar solutions , New J. Phys., 15 (2013), 045011

  11. [18]

    Jiang and N

    L. Jiang and N. Ou, Bayesian inference using intermediate distribution based on coarse mul- tiscale model for time fractional diffusion equations , Multiscale Model. Simul., 16 (2018), 327–355

  12. [19]

    Jin, Fractional differential equations-an approach via fractio nal derivatives , Appl

    B. Jin, Fractional differential equations-an approach via fractio nal derivatives , Appl. Math. Sci. 206, Springer, Cham, 2021

  13. [20]

    Larsson, V

    S. Larsson, V. Thom´ ee, L. W ahlbin, Numerical solution of parabolic integro-differential equa - tions by the discontinuous Galerkin method , Math. Comp., 67 (1998), 45–71

  14. [21]

    Y. Li, H. W ang, and X. Zheng, Analysis of a fractional viscoelastic Euler-Bernoulli bea m and identification of its piecewise continuous polynomial orde r, Fract. Calc. Appl. Anal., 26 (2023), 2337–2360

  15. [22]

    Lorenzo and T

    C. Lorenzo and T. Hartley, Variable order and distributed order fractional operators , Nonlinear Dyn., 29 (2002), 57–98

  16. [23]

    Lubich, Convolution quadrature and discretized operational calcu lus

    C. Lubich, Convolution quadrature and discretized operational calcu lus. I and II. , Numer. Math., 52 (1988), 129–145 and 413–425

  17. [24]

    McLean, I

    W. McLean, I. H. Sloan, V. Thom´ ee, Time discretization via Laplace transformation of an integro-differential equation of parabolic type , Numer. Math., 102 (2006), 497–522

  18. [25]

    Meerschaert, A

    M. Meerschaert, A. Sikorskii, Stochastic Models for Fractional Calculus , De Gruyter Studies in Mathematics, 2011

  19. [26]

    R. Meng, D. Yin, and C. Drapaca, Variable-order fractional description of compression def or- mation of amorphous glassy polymers , Comput. Mech., 64 (2019), 163–171

  20. [27]

    Mukherjee, P

    S. Mukherjee, P. Pareek, M. Barma, and S. Nandi, Stretched exponential to power-law: crossover of relaxation in a kinetically constrained model , J. Stat. Mech.: Theory Exp., 2024 (2024), 023205

  21. [28]

    Mustapha, H

    K. Mustapha, H. Mustapha, A second-order accurate numerical method for a semilinear integro-differential equation with a weakly singular kerne l, IMA J. Numer. Anal., 30 (2010), 555–578

  22. [29]

    Mustapha, H

    K. Mustapha, H. Brunner, H. Mustapha, D. Sch¨ otzau, An hp-version discontinuous Galerkin method for integro-differential equations of parabolic typ e, SIAM J. Numer. Anal., 49 (2011), 1369–1396

  23. [30]

    Orosco, C

    J. Orosco, C. F. M. Coimbra, Variable-order modeling of nonlocal emergence in many-bod y systems: Application to radiative dispersion , Phys. Rev. E, 98 (2018), 032208

  24. [31]

    A. K. Pani, G. Fairweather, R. I. Fernandes, ADI orthogonal spline collocation methods for parabolic partial integro-differential equations , IMA J. Numer. Anal., 30 (2010), 248–276

  25. [32]

    Podlubny, Fractional Differential Equations , Academic Press, 1999

    I. Podlubny, Fractional Differential Equations , Academic Press, 1999

  26. [33]

    L. Qiao, D. Xu, Compact alternating direction implicit scheme for integro -differential equations of parabolic type , J. Sci. Comput., 76 (2018), 565–582

  27. [34]

    Qiu, Optimal error estimate of an accurate second-order scheme f or Volterra integrod- ifferential equations with tempered multi-term kernels , Adv

    W. Qiu, Optimal error estimate of an accurate second-order scheme f or Volterra integrod- ifferential equations with tempered multi-term kernels , Adv. Comput. Math., 49 (2023), 43

  28. [35]

    H. Sun, A. Chang, Y. Zhang, and W. Chen, A review on variab le-order fractional differential equations: Mathematical foundations, physical models, nu merical methods and applica- 20 Qiu, Guo, Li, Guo and Zheng tions, Fract. Calc. Appl. Anal. , 22 (2019), 27–59

  29. [36]

    Xu, Uniform l1 Behavior for Time Discretization of a Volterra Equation wit h Completely Monotonic Kernel II: Convergence , SIAM J

    D. Xu, Uniform l1 Behavior for Time Discretization of a Volterra Equation wit h Completely Monotonic Kernel II: Convergence , SIAM J. Numer. Anal., 46 (2008), 231–259

  30. [37]

    Xu, Stability of the difference type methods for linear Volterra equations in Hilbert spaces , Numer

    D. Xu, Stability of the difference type methods for linear Volterra equations in Hilbert spaces , Numer. Math., 109 (2008), 571–595

  31. [38]

    Y. Yan, G. Fairweather, Orthogonal spline collocation methods for some partial int egrodiffer- ential equations , SIAM J. Numer. Anal., 29 (1992), 755–768

  32. [39]

    H. M. Yin, On parabolic Volterra equations in several space dimension s, SIAM J. Math. Anal., 22 (1991), 1723–1737

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