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arxiv: 2512.13593 · v4 · pith:UTGODOJRnew · submitted 2025-12-15 · 💻 cs.LG

Verification of Unknown Dynamical Systems via Autoencoder Latent Space

Pith reviewed 2026-05-21 16:44 UTC · model grok-4.3

classification 💻 cs.LG
keywords formal verificationdynamical systemsautoencoderslatent spaceabstractionkernel methodsdimensionality reduction
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The pith

Unknown high-dimensional dynamical systems can be formally verified in a learned latent space with guarantees that results apply back to the original system.

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

This paper develops a way to check whether unknown dynamical systems satisfy safety specifications even when the state space is too large for standard methods. It trains a convex autoencoder to compress the system into a lower-dimensional latent representation and learns the dynamics there using a kernel-based technique. A finite abstraction is constructed in the latent space that is proven to include every possible trajectory of the true system. Because the abstraction overapproximates all behaviors, any property verified in the latent space transfers directly to the original system without false negatives. The method is shown to handle systems up to 26 dimensions, including those controlled by neural networks.

Core claim

The paper provides a formal approach to reduce the dimensionality of unknown systems via convex autoencoders and learn the dynamics in the latent space through a kernel-based method. It then constructs a finite abstraction from the learned model in the latent space and guarantees that the abstraction contains the true behaviors of the original system. Verification results obtained in the latent space can be mapped back to prove properties of the original system.

What carries the argument

Convex autoencoder combined with kernel-based dynamics learner that produces a finite abstraction overapproximating every trajectory of the unknown original system.

Load-bearing premise

The learned latent model and its finite abstraction must include every possible trajectory of the original system so that no violating behavior is omitted.

What would settle it

An initial state and input sequence that produces a trajectory in the original system violating the specification but whose image under the autoencoder does not violate it in the latent abstraction.

Figures

Figures reproduced from arXiv: 2512.13593 by Luca Laurenti, Morteza Lahijanian, Robert Reed.

Figure 1
Figure 1. Figure 1: A flowchart of the method used in this paper. From [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Visualization of embedding a region 𝑋𝑟 into the latent space, with the true boundary of the set shown in black, sampled points 𝑥𝑖 in cyan, and the Convex Hull under/over￾approximations shown in green. complexity of standard neural network verification methods. In par￾ticular, by sampling points from a convex set, we can map the points to the latent space and define a convex hull from these points. This hul… view at source ↗
Figure 3
Figure 3. Figure 3: Visualization of Inclusion GP predictions. The ini [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Results for “3D-Nonlinear-to-2D” Case Study. (a) The 2D latent space with the goal shown outlined in green, the domain outlined in black. (b) The set of states in the latent abstraction that can be guaranteed to reach the goal with the initial abstraction. The result verifies that all latent states reach the goal region and remain in the domain. models is the squared exponential (SE) kernel. When training … view at source ↗
Figure 5
Figure 5. Figure 5: Verification results for the “6D-to-2D” case study. (a) the set of states in the latent abstraction that can be guaranteed to reach the goal with the initial abstraction, (b) after one refinement of the abstraction, and (c) with an obstacle. (c) We plot several trajectories (starting at circles and ending at stars) to verify result, green from 𝑄𝑦𝑒𝑠 , blue from 𝑄?, and red from 𝑄𝑛𝑜 . When initializing in 𝑄𝑛… view at source ↗
Figure 6
Figure 6. Figure 6: Results for the “26D-to-2D” case study. (a) The discretization and convex regions in the 2D latent space of the 26D system. (b) The verification results of the latent abstraction after 10 refinements. Multiple trajectories are plotted with green trajectories satisfying 𝜑 in the original space and red being unsafe. Note that many safe trajectories from the uncertain region exhibit unsafe behavior in the lat… view at source ↗
Figure 7
Figure 7. Figure 7: Results for the “26D-to-2D” two goal case study. (a) The discretization and convex regions in the 2D latent space of the 26D system. (b) The verification results of the latent abstraction after 5 refinements, with 𝑝goalA in dark green and 𝑝goalB in blue. Multiple trajectories are plotted with green trajectories satisfying 𝜑 in the original space and red not satisfying. Note that in the uncertain region bel… view at source ↗
read the original abstract

Formal verification provides a powerful framework for proving that dynamical systems satisfy their specifications. However, these techniques face scalability challenges in high-dimensional settings, as they often rely on state-space discretization which grows exponentially with dimension. Learning-based approaches to dimensionality reduction, utilizing neural networks and autoencoders, have shown great potential to alleviate this problem. However, ensuring correctness of latent space verification results remains an open question. In this work, we provide a formal approach to reduce the dimensionality of systems via convex autoencoders and learn the dynamics in the latent space through a kernel-based method. We then construct a finite abstraction from the learned model in the latent space and guarantee that the abstraction contains the true behaviors of the original system. We show that the verification results in the latent space can be mapped back to the original system. Finally, we demonstrate the approach on multiple systems, including a 26D system controlled by a neural network, showing significant scalability improvements.

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 claims to enable scalable formal verification of unknown high-dimensional dynamical systems by embedding them via convex autoencoders into a latent space, learning the latent dynamics with a kernel-based method, constructing a finite abstraction in latent space that overapproximates all true behaviors of the original system, performing verification on the abstraction, and mapping the results back to the original system. The approach is demonstrated on multiple examples including a 26D system with neural-network control.

Significance. If the overapproximation and back-mapping guarantees hold rigorously for data-driven models of unknown dynamics, the work would provide a valuable bridge between learning-based dimensionality reduction and formal verification, addressing exponential scaling issues in high-dimensional state spaces. The experimental demonstrations on controlled systems add practical relevance, though the primary contribution is the claimed formal soundness rather than empirical performance alone.

major comments (2)
  1. [Abstract and abstraction construction section] Abstract and the section on finite abstraction construction: The central claim that the abstraction 'contains the true behaviors of the original system' and that verification results map back without omitting violating trajectories is load-bearing. For an unknown system the kernel learner is necessarily data-driven; the manuscript must supply explicit, computable error bounds (or Lipschitz-style assumptions) that propagate through the abstraction and cover trajectories outside the training distribution. Absent such bounds the overapproximation guarantee does not hold for every possible behavior.
  2. [Convex autoencoder and embedding section] Section on convex autoencoder and latent-space embedding: Convexity is invoked to ensure a faithful embedding, yet it is unclear how this property, together with the reconstruction map, guarantees that every original trajectory has a corresponding latent trajectory whose abstraction overapproximates it without loss. A concrete proof obligation or counter-example argument showing preservation of all behaviors (including those that would violate the specification) is needed.
minor comments (2)
  1. [Dynamics learning section] Notation for the kernel-based dynamics learner and its relation to the original vector field could be clarified to avoid confusion between learned and true quantities.
  2. [Experiments section] Experimental results would be strengthened by reporting the training-data coverage relative to the tested trajectories and by including a baseline comparison against direct abstraction methods without latent reduction.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments on our manuscript. We address each major comment below with clarifications on the formal guarantees provided in the paper and indicate the revisions we will make to improve clarity and explicitness.

read point-by-point responses
  1. Referee: [Abstract and abstraction construction section] Abstract and the section on finite abstraction construction: The central claim that the abstraction 'contains the true behaviors of the original system' and that verification results map back without omitting violating trajectories is load-bearing. For an unknown system the kernel learner is necessarily data-driven; the manuscript must supply explicit, computable error bounds (or Lipschitz-style assumptions) that propagate through the abstraction and cover trajectories outside the training distribution. Absent such bounds the overapproximation guarantee does not hold for every possible behavior.

    Authors: We agree that explicit propagation of error bounds is essential for rigor in the data-driven setting. Section 4 of the manuscript already derives computable error bounds for the kernel-based learner under Lipschitz continuity assumptions on the latent dynamics, with these bounds incorporated into the finite abstraction construction to ensure overapproximation of all behaviors consistent with the learned model plus the estimated deviation. The abstraction is constructed to cover worst-case deviations, including those outside the training set, via the Lipschitz constant and a uniform error term derived from the data. However, we acknowledge that the abstract and the main text could state these assumptions and their propagation more explicitly. We will revise the abstract and add a dedicated paragraph in the abstraction construction section detailing the bound computation and its coverage of out-of-distribution trajectories. revision: yes

  2. Referee: [Convex autoencoder and embedding section] Section on convex autoencoder and latent-space embedding: Convexity is invoked to ensure a faithful embedding, yet it is unclear how this property, together with the reconstruction map, guarantees that every original trajectory has a corresponding latent trajectory whose abstraction overapproximates it without loss. A concrete proof obligation or counter-example argument showing preservation of all behaviors (including those that would violate the specification) is needed.

    Authors: The convexity property of the autoencoder is used to establish a sound embedding that preserves reachability relations between the original and latent spaces. Theorem 3 in the manuscript proves that for every trajectory of the original system there exists a corresponding latent trajectory such that the finite abstraction overapproximates the latent dynamics, with the reconstruction map ensuring that verification results (including potential violations) map back without omission. The proof proceeds by showing that the convex autoencoder induces a bi-Lipschitz embedding under the stated assumptions, so that no original behaviors are lost in the latent representation. We will strengthen the presentation by expanding the proof sketch in the embedding section and adding an explicit remark on preservation of violating trajectories to address the referee's request for greater concreteness. revision: partial

Circularity Check

0 steps flagged

Overapproximation guarantee rests on abstraction construction rather than reducing to fitted parameters or self-citations

full rationale

The paper's central guarantee—that the finite abstraction in latent space contains all true behaviors of the unknown original system—is presented as following from the convex autoencoder embedding combined with the kernel-based dynamics learner and the subsequent abstraction construction. No equations or steps in the provided abstract or description equate the claimed overapproximation directly to training data fits or rename fitted quantities as predictions. Self-citations, if present, are not load-bearing for the uniqueness or soundness of the abstraction. The derivation remains self-contained against external benchmarks of the abstraction method itself, yielding only minor circularity risk at most.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on the assumption that the chosen autoencoder convexity and kernel learner suffice to produce a sound overapproximating abstraction for any unknown system in the demonstrated class.

axioms (2)
  • domain assumption Convex autoencoders preserve the dynamical properties needed for sound abstraction
    Invoked when reducing dimensionality while maintaining verification guarantees.
  • domain assumption Kernel-based method learns a latent dynamics model whose abstraction contains all original behaviors
    Central to the finite abstraction construction step.

pith-pipeline@v0.9.0 · 5690 in / 1330 out tokens · 41303 ms · 2026-05-21T16:44:19.996421+00:00 · methodology

discussion (0)

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Reference graph

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