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arxiv: 2510.17421 · v2 · submitted 2025-10-20 · 💻 cs.LG

Diffusion Models as Dataset Distillation Priors

Pith reviewed 2026-05-18 06:00 UTC · model grok-4.3

classification 💻 cs.LG
keywords dataset distillationdiffusion modelsMercer kernelrepresentativeness priorreverse diffusionsynthetic datacross-architecture generalization
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The pith

Diffusion models carry an inherent representativeness prior that a Mercer kernel can extract to guide the reverse diffusion process and improve dataset distillation without retraining.

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

Dataset distillation tries to turn large real datasets into small synthetic ones that still support good model training. The paper establishes that diffusion models already embed a useful prior for making synthetic samples representative of real ones, a prior that prior work overlooked. It formalizes this prior as the similarity between synthetic and real data points measured by a Mercer kernel in feature space, then injects the resulting signal to steer the denoising steps. A sympathetic reader would care because the method needs no extra training of the diffusion model yet delivers higher-fidelity synthetic data with stronger generalization across neural-network architectures on large-scale sets such as ImageNet-1K.

Core claim

DAP formalizes representativeness by quantifying the similarity between synthetic and real data in feature space using a Mercer kernel and introduces this prior as guidance to steer the reverse diffusion process, enhancing the representativeness of distilled samples without any retraining. This establishes a theoretical connection between diffusion priors and the objectives of dataset distillation while providing a practical, training-free framework for improving the quality of the distilled dataset.

What carries the argument

The DAP guidance term, which computes Mercer-kernel similarity in feature space and adds it as a steering signal during reverse diffusion to enforce representativeness in the generated samples.

If this is right

  • Distilled datasets achieve higher fidelity on ImageNet-1K and its subsets than existing methods.
  • The synthetic data exhibits superior generalization when used to train models of different architectures.
  • No retraining of the underlying diffusion model is needed to apply the improvement.
  • A direct theoretical link is drawn between the generative prior in diffusion models and the goals of dataset distillation.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same kernel-based prior extraction might be adapted to other generative models to boost their use in data synthesis tasks.
  • Because the method is training-free it could allow rapid testing of new distillation objectives on existing diffusion checkpoints.
  • The approach hints that diffusion sampling trajectories can be lightly modified to enforce additional dataset properties such as explicit diversity control.

Load-bearing premise

That similarity measured by a Mercer kernel in feature space correctly captures the representativeness prior of diffusion models and that adding this guidance during the reverse process improves distilled data quality without harming diversity or generalization.

What would settle it

Train models on datasets distilled with and without the Mercer-kernel guidance on an ImageNet subset, then measure both downstream accuracy on real test data and cross-architecture transfer; consistent gains only with the guidance would support the claim, while equal or worse results would falsify it.

Figures

Figures reproduced from arXiv: 2510.17421 by Duo Su, Huanran Chen, Huyu Wu, Jun Zhu, Xi Ye, Yiming Shi, Yuzhu Wang.

Figure 1
Figure 1. Figure 1: Our diffusion as priors (DAP) method is beneficial for the DD task. Diversity: 1+FIDmax−FID. Represen￾tativeness: 1 d(ϕ(x),ϕ(y)) . Performance: classification results on ImageNet-1K. We propose Diffusion As Priors (DAP) and apply it to datasets of varying scales, including large-scale ImageNet-1K (Deng et al., 2009) and its small subsets. Both quantitative and qualitative results show that DAP significantl… view at source ↗
Figure 2
Figure 2. Figure 2: Visualization of average representativeness (∝ 1 d(ϕ(x),ϕ(y)) ) of distilled samples (IPC10). As γ increases, the representativeness (sector area) gets larger, yielding better DD performance. gradient field of diversity and generalization (∇x log p(x)) is determined and fixed by pre-trained DMs. Therefore, the gradient field of representativeness cannot be increased indefinitely, otherwise the other priors… view at source ↗
Figure 3
Figure 3. Figure 3: The comparison results on Stable Diffusion. The results are evaluated with both hard￾label (HL) and soft-label (SL) protocols based on ResNet-18. The results of SL protocol are marked with a light blue background, while those without background color are from HL protocol. 8 [PITH_FULL_IMAGE:figures/full_fig_p008_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Visualization results of t-SNE. We compare the feature distribution of real (training and [PITH_FULL_IMAGE:figures/full_fig_p009_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Ablation studies under ResNet-18. (a-b) Top-1 Accuracy under different backbone layer selection. (c-d) Top-1 Accuracy under varied guidance scale γ. 5 CONCLUSION This paper introduces Diffusion as Priors, a framework for dataset distillation that leverages the in￾herent priors of diffusion models. We identify diversity, generalization, and representativeness priors in diffusion models, and demonstrate how … view at source ↗
Figure 6
Figure 6. Figure 6: A sketch map of the relationship between [PITH_FULL_IMAGE:figures/full_fig_p016_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Curves of different Mer￾cer kernel-induced distances [PITH_FULL_IMAGE:figures/full_fig_p017_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Ablation study on tstop selection. A.4.6 SAMPLING-TIME SCALING DAP does not introduce additional training costs, since no external pre-training or fine-tuning is required. The representativeness prior is directly derived from the pre-trained diffusion backbone. However, to inject this prior during sampling and improve data quality, we must extract features from the noisy training data x train t using the b… view at source ↗
Figure 9
Figure 9. Figure 9: Samples distilled by DiT (left three columns) and SD (right three columns). The excessive [PITH_FULL_IMAGE:figures/full_fig_p019_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Visualization results of different DD methods. At the bottom of each group, we use the [PITH_FULL_IMAGE:figures/full_fig_p020_10.png] view at source ↗
read the original abstract

Dataset distillation aims to synthesize compact yet informative datasets from large ones. A significant challenge in this field is achieving a trifecta of diversity, generalization, and representativeness in a single distilled dataset. Although recent generative dataset distillation methods adopt powerful diffusion models as their foundation models, the inherent representativeness prior in diffusion models is overlooked. Consequently, these approaches often necessitate the integration of external constraints to enhance data quality. To address this, we propose Diffusion As Priors (DAP), which formalizes representativeness by quantifying the similarity between synthetic and real data in feature space using a Mercer kernel. We then introduce this prior as guidance to steer the reverse diffusion process, enhancing the representativeness of distilled samples without any retraining. Extensive experiments on large-scale datasets, such as ImageNet-1K and its subsets, demonstrate that DAP outperforms state-of-the-art methods in generating high-fidelity datasets while achieving superior cross-architecture generalization. Our work not only establishes a theoretical connection between diffusion priors and the objectives of dataset distillation but also provides a practical, training-free framework for improving the quality of the distilled dataset.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper proposes Diffusion As Priors (DAP) for dataset distillation. It formalizes representativeness by quantifying similarity between synthetic and real data in feature space via a Mercer kernel, then uses this quantity as guidance to steer the reverse diffusion process of a pre-trained model. The approach is training-free and is claimed to improve fidelity and cross-architecture generalization on ImageNet-1K and subsets relative to prior generative distillation methods, while establishing a theoretical link between diffusion priors and distillation objectives.

Significance. If the Mercer-kernel guidance is shown to encode an inherent diffusion prior (rather than an external regularizer) and the reported gains are robust, the work would supply a principled, retraining-free mechanism for enhancing representativeness in generative dataset distillation. This could influence downstream efficiency in large-scale training pipelines and strengthen connections between score-based generative models and data-synthesis objectives.

major comments (2)
  1. [§3] §3 (guidance term derivation): the manuscript must demonstrate that the Mercer-kernel similarity is derived from the diffusion model's score function or reverse SDE rather than introduced as an independent external penalty. If the feature extractor is separate from the diffusion backbone, the construction risks reducing to heuristic classifier-free guidance plus a similarity term, undermining the claimed 'inherent representativeness prior' and the theoretical connection asserted in the abstract.
  2. [§4] §4 (experiments): the central claim of outperformance and improved generalization rests on quantitative results that are not visible in the abstract; the full paper must include ablations on guidance strength, diversity metrics, and failure cases. Without these, it is impossible to verify whether the prior improves representativeness without trading off other desiderata.
minor comments (2)
  1. [Abstract] Abstract: include at least one concrete performance number (e.g., top-1 accuracy or distillation ratio) to support the outperformance claim.
  2. [Notation] Notation: define the Mercer kernel, feature extractor, and guidance coefficient explicitly with equation numbers to prevent ambiguity in how the similarity term is computed and scaled.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the detailed and constructive comments. We address each major comment below and outline the revisions we will make to the manuscript.

read point-by-point responses
  1. Referee: [§3] §3 (guidance term derivation): the manuscript must demonstrate that the Mercer-kernel similarity is derived from the diffusion model's score function or reverse SDE rather than introduced as an independent external penalty. If the feature extractor is separate from the diffusion backbone, the construction risks reducing to heuristic classifier-free guidance plus a similarity term, undermining the claimed 'inherent representativeness prior' and the theoretical connection asserted in the abstract.

    Authors: We appreciate this insightful comment. In the original manuscript, the guidance term is introduced by modifying the reverse diffusion process to incorporate the representativeness prior, which is quantified using the Mercer kernel on features extracted from real and synthetic data. This is not merely an external penalty but is integrated into the sampling trajectory of the pre-trained diffusion model, thereby leveraging its inherent prior. The feature extractor is a separate component used to define the similarity measure in a semantically meaningful space, similar to how classifier guidance uses an external classifier. To strengthen the theoretical connection, we will revise §3 to include a step-by-step derivation showing how this guidance arises from adjusting the score function in the reverse SDE to favor representative samples. This will clarify that it encodes the diffusion prior rather than acting as a standalone regularizer. revision: yes

  2. Referee: [§4] §4 (experiments): the central claim of outperformance and improved generalization rests on quantitative results that are not visible in the abstract; the full paper must include ablations on guidance strength, diversity metrics, and failure cases. Without these, it is impossible to verify whether the prior improves representativeness without trading off other desiderata.

    Authors: Thank you for pointing this out. While the abstract summarizes the main results, the full manuscript in §4 presents quantitative comparisons on ImageNet-1K and subsets, showing improvements in fidelity and cross-architecture generalization. To address the request for more comprehensive analysis, we will add ablations on the guidance strength parameter, including its effect on representativeness and other metrics. We will also report diversity metrics (e.g., pairwise similarity or coverage) and discuss potential failure cases, such as when the prior overly constrains diversity. These additions will be included in the revised §4 to provide a more complete verification of the method's benefits. revision: yes

Circularity Check

0 steps flagged

Representativeness prior is defined as Mercer-kernel feature similarity then re-introduced as guidance to improve that same similarity

full rationale

The paper's core move is to define the 'inherent representativeness prior' of diffusion models explicitly as a Mercer-kernel similarity between synthetic and real features, then add that quantity as a guidance term during reverse diffusion. This construction is self-contained and does not reduce the final distilled dataset to a fitted parameter or self-citation chain; the guidance is an external regularizer applied to a pre-trained diffusion model. No equations are shown that make the guidance term mathematically identical to the distillation objective by definition, and no load-bearing self-citation is invoked to justify uniqueness. The derivation therefore remains non-circular, though the claim that the kernel similarity is 'inherent' to the diffusion model rather than an added heuristic is a separate correctness question.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the assumption that feature-space Mercer kernel similarity faithfully encodes the diffusion model's representativeness prior and that this quantity can be injected as guidance without side effects. No free parameters or invented entities are explicitly named in the abstract.

axioms (1)
  • domain assumption Mercer kernel similarity in feature space accurately quantifies representativeness between synthetic and real data.
    Invoked when the paper states it formalizes representativeness by quantifying similarity using a Mercer kernel.

pith-pipeline@v0.9.0 · 5731 in / 1336 out tokens · 40773 ms · 2026-05-18T06:00:27.492081+00:00 · methodology

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Reference graph

Works this paper leans on

12 extracted references · 12 canonical work pages

  1. [1]

    Language models are few-shot learners.Advances in neural information processing systems, 33:1877–1901,

    Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners.Advances in neural information processing systems, 33:1877–1901,

  2. [2]

    Mgdˆ3: Mode-guided dataset distillation using diffusion models.arXiv preprint arXiv:2505.18963,

    Jeffrey A Chan-Santiago, Praveen Tirupattur, Gaurav Kumar Nayak, Gaowen Liu, and Mubarak Shah. Mgdˆ3: Mode-guided dataset distillation using diffusion models.arXiv preprint arXiv:2505.18963,

  3. [3]

    Available athttps://arxiv.org/ abs/2205.03257

    10 Preprint. Under Review. Jeremy Howard. Imagenette: A smaller subset of 10 easily classified classes from imagenet, March 2019a. URLhttps://github.com/fastai/imagenette. Jeremy Howard. Imagewoof: a subset of 10 classes from imagenet that aren’t so easy to classify, March 2019b. URLhttps://github.com/fastai/imagenette#imagewoof. James Jordon, Lukasz Szpr...

  4. [4]

    The evolution of dataset distillation: Toward scalable and generalizable solutions,

    Ping Liu and Jiawei Du. The evolution of dataset distillation: Toward scalable and generalizable solutions.arXiv preprint arXiv:2502.05673,

  5. [5]

    Scaling laws of synthetic data for language models.arXiv preprint arXiv:2503.19551,

    Zeyu Qin, Qingxiu Dong, Xingxing Zhang, Li Dong, Xiaolong Huang, Ziyi Yang, Mahmoud Khademi, Dongdong Zhang, Hany Hassan Awadalla, Yi R Fung, et al. Scaling laws of synthetic data for language models.arXiv preprint arXiv:2503.19551,

  6. [6]

    DiM: Distill- ing dataset into generative model,

    Kai Wang, Jianyang Gu, Daquan Zhou, Zheng Zhu, Wei Jiang, and Yang You. Dim: Distilling dataset into generative model.arXiv preprint arXiv:2303.04707,

  7. [7]

    Dataset Distillation , journal =

    Tongzhou Wang, Jun-Yan Zhu, Antonio Torralba, and Alexei A Efros. Dataset distillation.arXiv preprint arXiv:1811.10959,

  8. [8]

    Hierar- chical features matter: A deep exploration of gan priors for improved dataset distillation.arXiv preprint arXiv:2406.05704,

    Xinhao Zhong, Hao Fang, Bin Chen, Xulin Gu, Tao Dai, Meikang Qiu, and Shu-Tao Xia. Hierar- chical features matter: A deep exploration of gan priors for improved dataset distillation.arXiv preprint arXiv:2406.05704,

  9. [9]

    imitation

    12 Preprint. Under Review. A APPENDIX Appendix organization: Section A.1: Background A.1.1: Dataset distillation A.1.2: Generative dataset distillation Section A.2: Proofs A.2.1: Validity of kernel-induced distance A.2.2: Distance factorization Section A.3: Experimental Setup A.3.1: Datasets and benchmarks A.3.2: Models and evaluation protocols A.3.3: Oth...

  10. [10]

    H-PD (Zhong et al.,

    enhances cross-architecture generalization by distilling data into the latent space of pre-trained models like StyleGAN (Karras et al., 2019). H-PD (Zhong et al.,

  11. [11]

    • Symmetry:∥ϕ(x)−ϕ(y)∥=∥ϕ(y)−ϕ(x)∥

    there exists a repro- ducing kernel Hilbert spaceHand a feature mapϕ:X → Hsuch that K(x, y) =⟨ϕ(x), ϕ(y)⟩ H.(10) Therefore, DK(x, y)2 =K(x, x) +K(y, y)−2K(x, y)(11) =⟨ϕ(x), ϕ(x)⟩ H +⟨ϕ(y), ϕ(y)⟩ H −2⟨ϕ(x), ϕ(y)⟩ H (12) =∥ϕ(x)−ϕ(y)∥ 2 H.(13) Thus, DK(x, y) =∥ϕ(x)−ϕ(y)∥ H.(14) Since the norm in Hilbert space∥ · ∥ H is a valid metric, it satisfies: • Non-neg...

  12. [12]

    A.3.2 MODELS AND EVALUATION PROTOCOLS For each dataset, we distill subsets of 10, 50, and 100 images per class (IPC) and assess their utility on downstream classification tasks

    to evaluate performance. A.3.2 MODELS AND EVALUATION PROTOCOLS For each dataset, we distill subsets of 10, 50, and 100 images per class (IPC) and assess their utility on downstream classification tasks. Two evaluation protocols are adopted: • Hard-label protocol: Following Chen et al. (2025), we directly train classifiers from scratch using the distilled ...