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REVIEW 3 major objections 5 minor 29 references

Systems Engineering for Autonomous Vehicles; Supervising AI using Large Language Models (SSuperLLM)

T0 review · 3 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

Pith's one-line read The paper claims that LLMs can carry out real systems-engineering work for autonomous vehicles—requirements writing, requirements auditing, and runtime supervisory control—and demonstrates the supervisory piece in a simulation.

desk verdict A transparent, honest proof-of-concept for LLM-based supervisory control of an AV, but the evidence is a single run and the known rule ambiguity is never actually tested. read the letter →

arxiv 2501.10839 v1 pith:3LVQBYDQ submitted 2025-01-18 eess.SY cs.SY

classification eess.SYcs.SY
keywords autonomousvehicleslargelanguagemodelssystemsengineeringrequirementssupervisorycontrolV-modelLQRsafetyoftheintendedfunctionality
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

Autonomous-vehicle development is expensive partly because requirements work is manual and hard to verify. This paper proposes that large language models can take on part of that systems-engineering workload: generating and decomposing requirements, auditing human-written requirements against criteria like clarity and measurability, and acting as a supervisory layer that monitors the vehicle's behavior in real time. To support the supervisory claim, it runs a simulation of a planar bicycle vehicle model with LQR lateral control and a set of seven atomic safety rules for pedestrian jaywalking; with a 0.5 s LLM decision period the supervisor issues correct braking and nudging commands, and with a 2 s period it misses a collision. The paper concludes that the proof-of-concept supports the hypothesis, with the caveat that requirements must be unambiguous and humans must stay in the loop.

What carries the argument

The mechanism is an LLM-based supervisory monitor layered over a conventional vehicle controller. The architecture has three working parts: an offboard-generated approved behavior database of atomic, self-contained rules; a context-translation layer that converts numerical state (longitudinal distance, lateral offset, speed, braking distances, predicted pedestrian position) into a natural-language prompt; and an LLM API that returns a fixed-format command like 'Req=2, accel=-2, nudge=1' which the simulation parses. The lower-level plant is a 3-DOF planar bicycle model with time-varying LQR lateral control, and the rules encode speed-maintenance, soft/medium/hard/full braking, and nudging behavior for jaywalking pedestrians. The fixed-response format is what makes the loop testable: the LLM's language output is constrained so a program can act on it deterministically.

What would settle it

Run the supplied simulation with scenario parameters that place the expected pedestrian position exactly at the boundary between 'close crossing' and 'in the middle of the road', and tabulate the LLM's returned requirement over many runs; if the wrong braking command appears at an appreciable rate even with the atomic rule set, the claim of reliable supervisory control fails.

Watch

Extended reading notes

Core claim

The paper's central claim is that an LLM can serve as a usable supervisory controller for an autonomous vehicle—not by driving directly, but by turning a context translation of the current vehicle and pedestrian state into a natural-language query, matching that query against an approved set of atomic requirements, and returning a fixed-format action command that a lower-level controller executes. At a 0.5 s call period, this worked in simulation. At a 2 s call period, it failed and produced a virtual vehicle-pedestrian overlap. The paper also reports that an earlier, less carefully worded rule set caused the LLM to confuse 'close crossing' with 'in the middle of the road' and issue a hard-brake command where soft braking was intended, which the paper treats as evidence that requirements must be written explicitly and atomically. The stated conclusion is that LLMs are a productivity multiplier for systems engineering, not a replacement for humans.

Load-bearing premise

The scheme works only if the LLM reliably maps a plain-language description of the situation to the correct rule whenever the rules are written atomically and self-containedly; the paper's own example shows that near-threshold wording can break this mapping.

Editorial extensions

If this is right

  • At a 0.5 s LLM decision period, the supervisory monitor produced correct braking and nudging commands through the whole simulation and no vehicle-pedestrian overlap occurred.
  • At a 2 s LLM decision period, the same supervisor missed the developing situation and a virtual overlap between vehicle and pedestrian occurred, so supervision frequency is a hard constraint.
  • Requirements for the LLM must be atomic, self-contained, clear, measurable, unambiguous, and non-overlapping; an earlier rule formulation made the LLM confuse 'close crossing' with 'in the middle of the road' and issue the wrong braking command.
  • The same LLM capability can audit human-written requirements against criteria such as specificity and measurability, and can help decompose a parent requirement into children whose satisfaction implies the parent is satisfied.
  • The paper's own conclusion is that these uses make LLMs a productivity multiplier for systems engineering, with humans still required to write and approve rules before the system is trusted.

Reading between the lines

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

  • Reader's inference: the runtime LLM in this design is doing rule classification rather than traffic reasoning; once the rules are fixed, the same loop could run with a deterministic parser, so the LLM's distinctive value is probably in generating and auditing the rule set rather than in live decision-making.
  • Testable extension: rewrite the state predicates with explicit numeric thresholds and rerun the near-threshold cases from Section 5.2.3; if the errors disappear, the bottleneck is wording, not the LLM's capability.
  • Design implication: the 2 s failure means a supervisory monitor needs a guaranteed response-latency budget, so the LLM's variable latency becomes a safety parameter that must be bounded before deployment.
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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

3 major / 5 minor

Summary. The paper proposes using Large Language Models (LLMs) throughout the systems-engineering lifecycle of autonomous vehicles: requirements development, requirements audit, functional decomposition, and online supervisory control. After advocating the architecture on general grounds, it presents a proof-of-concept in which a Gemini LLM is prompted with seven natural-language rules and, through a context-translation layer, selects acceleration and nudge commands for a simulated bicycle-model vehicle with an LQR lateral controller. The paper reports a successful run with a 0.5 s LLM call period, a failed run with a 2 s period, and a documented earlier failure in which the LLM confused "close crossing" with "in the middle of the road," producing an incorrect braking command. The discussion concludes that the proof-of-concept shows the hypothesis is true, while cautioning that more research is needed.

Significance. If the central claim were established, the paper would make a useful contribution to explainable supervisory control for autonomous vehicles: an external LLM could audit rule-based behavior selections and produce human-readable justifications, and LLM-assisted requirements work would accelerate a bottleneck in systems engineering. The paper also has practical merits: the simulation is transparent, the vehicle dynamics and LQR design are standard, the source of the demonstrated failure is honestly reported, and the Colab software is made openly available. The evidence, however, is not yet commensurate with the conclusion. The successful run is a single trajectory that does not exercise the previously failing semantic distinction, and no quantitative evaluation of rule-selection accuracy or safety margin is provided. The significance of the idea is therefore real but the support is preliminary.

major comments (3)
  1. [5.2.1 and 5.2.3] The successful 0.5 s run does not exercise the rules that the LLM previously failed. The reported LLM interactions select only Req=2 and Req=7, and no state description in Section 5.2.1 contains the phrase "expected to be in the middle of the road," which would trigger Req=4 or Req=5. Section 5.2.3 documents that in the older rule formulation the LLM mapped a "close crossing" state to "Req.3, accel=-4,nudge=no," i.e., it applied medium braking instead of soft braking with a nudge. The revised rules in Section 5.1 change the wording but provide no evidence that the ambiguity is resolved, because the successful run simply avoids the problematic states. Since the confused state corresponds to a pedestrian partially across the road, the central claim that the LLM reliably supervises AV behavior is not established by the presented data.
  2. [5.2 and 6] The empirical basis for the proof-of-concept is a single successful trajectory. The paper reports one run at LLMCallPeriod_s=0.5 and one failed run at LLMCallPeriod_s=2, with no statistical replication, no sensitivity analysis over prompts or rule phrasings, no comparison against a non-LLM baseline, and no quantitative safety metric such as minimum separation, time-to-collision, or rule-selection accuracy. The statement in Section 6 that "the proof-of-concept shows that our hypothesis for LLM and SysEng is true" is therefore too strong. The authors should either add a systematic evaluation over multiple runs and states or temper the conclusion to a preliminary demonstration.
  3. [5.1 and 5.2.2] The comparison between the 0.5 s and 2 s runs conflates the LLM's rule-selection quality with the supervisory control period. The 2 s run shows a "virtual spatial overlap" between vehicle and pedestrian, but this could be due to the low decision rate rather than to a failure of the LLM to select the correct rule. The LLM's mapping from state text to rule should be evaluated independently of the closed-loop control period, for example by presenting the full set of relevant states offline and measuring classification accuracy against a ground-truth labeling.
minor comments (5)
  1. [5.2.2] The text says "Refer to Fig. 7" for the LLMCallPeriod_s=2 case, but the relevant figure is Fig. 8; this makes the failed run harder to locate.
  2. [3.2] The phrase "It is truly impressive!" is informal for a journal; a neutral description of the audit output would be more appropriate.
  3. [4] The list of contributions is introduced as "following steps a) to d)" but the items are numbered 1 to 4; the cross-reference should be harmonized.
  4. [5.1] The rules use semantically loaded terms such as "close crossing" and "in the middle of the road" without an explicit operational definition; stating the intended geometric or temporal thresholds would help readers assess whether the revised rules are genuinely more precise.
  5. [7.2] The LQR weights Q and R are given in the footnote to the code snippet, but they are not included in the main text or in a parameter table; moving them into the appendix text would improve reproducibility.

Circularity Check

0 steps flagged · score 1.0 of 10

No circular reduction: the LLM is an external oracle, and the rules and commands are set before the run rather than fitted to the outcome.

full rationale

I found no circular step that fits the required patterns. The proof-of-concept is empirical: the LLM (Gemini) is invoked through an API and its text responses are parsed into acceleration and nudge commands; the seven rules and command strings in Section 5.1 are authored before the simulation and are not fitted to make the run succeed. The vehicle dynamics and LQR in Section 7 are standard and independent of the LLM. Most informative is Section 5.2.3, where the same style of prompt produced a wrong selection (the LLM answered Req.3 where the paper expected the harder-braking rule), showing that the LLM output is not forced by construction. Section 6 further concedes that LLM maturity and atomic, self-contained rules matter and that caution is needed before definitive conclusions. The self-citation to reference [9] for the SysEng V-model and parent-child requirement decomposition is background methodology, not load-bearing evidence for the empirical claim. The skeptic concern that the successful run does not exercise the ambiguous middle-of-the-road states is a validation-gap argument, not a circularity argument, so it does not raise the circularity score.

Assumptions & free parameters 2 free parameters · 5 assumptions · 0 invented entities

The paper introduces no new physical entities. It relies on standard vehicle dynamics, LQR control, and the assumption that a carefully prompted LLM will follow rules reliably. The main free parameters are the LQR weights and the braking deceleration levels, which are hand-set and could affect the demonstration's outcome.

free parameters (2)
  • LQR weights Q and R = Q=diag([0.5, 0.3, 0, 0.3]), R=[5]
    Hand-chosen by the author for lateral tracking; affect path-following quality and are not learned from data.
  • Deceleration levels for braking (soft, medium, hard, very hard) = -2, -4, -6, -8 m/s^2
    Set in the prompt rules to define the vehicle's braking response; chosen by the author, not derived from safety analysis.
assumptions (5)
  • domain assumption Bicycle model (3-DOF) with linear tire stiffness is a sufficient representation of the vehicle for this proof-of-concept.
    Used in Section 7.1; assumes small slip angles and constant cornering stiffness.
  • standard math The LQR with the linearized model (8) provides adequate lateral control for the simulated scenarios.
    Standard control theory; the linearization is valid around operating points, and Q/R chosen by the author.
  • domain assumption A well-formed, atomic requirement set is unambiguous to an LLM, so the LLM will select the correct rule.
    This is the core reliability assumption for the supervisory monitor; contradicted by the older-rule example in Section 5.2.3.
  • domain assumption SysEng decomposition principle: if all child requirements are met, the parent requirement is met.
    Invoked in Section 1 and 3.3 as foundational for Req-based safety.
  • domain assumption The simulation scenario (two jaywalking pedestrians, fixed speeds) is representative enough to test the supervisory concept.
    Used in Section 5; no sensitivity analysis or varied traffic conditions.

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Cite this review

Pith. "Pith review of Systems Engineering for Autonomous Vehicles; Supervising AI using Large Language Models (SSuperLLM)." pith.science (2026). https://pith.science/paper/3LVQBYDQ

@misc{pith2026250110839,
  author       = {Pith},
  title        = {Pith review of: Systems Engineering for Autonomous Vehicles; Supervising AI using Large Language Models (SSuperLLM)},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/3LVQBYDQ}},
  note         = {Machine review of arXiv:2501.10839}
}
read the original abstract

Generative Artificial Intelligence (GAI) and the idea to use hierarchical models has been around for some years now. GAI has proved to be an extremely useful tool for Autonomous Vehicles (AVs). AVs need to perform robustly in their environment. Thus the AV behavior and short-term trajectory planning needs to be: a) designed and architected using safeguarding and supervisory systems and b) verified using proper Systems Engineering (SysEng) Principles. Can AV Systems Engineering also use Large Language Models (LLM) to help Autonomous vehicles (AV) development? This reader-friendly paper advocates the use of LLMs in 1) requirements (Reqs) development and 2) Reqs verification and 3) provides a proof-of-concept of AV supervisory control. The latter uses a simulation environment of a simple planar (bicycle) vehicle dynamics model and a Linear Quadratic Regulator (LQR) control with an LLM Application Interface (API). The Open-Source simulation SW is available from the author accessible to the readers so that they can engage into the AV stack, LLM API and rules, SysEng and Reqs and fundamental vehicle dynamics and control.

Figures

Figures reproduced from arXiv: 2501.10839 by the authors.

Figure 1
Figure 1. The V-model of the systems engineering process [9]. VnV feedbacks back to architecture and Reqs. [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Part of the answer of ChatGPT-3.5 in the question “What are the basic manoeuvres in driving a car?” [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. LLM for functional decomposition and Reqs coverage assessment. The “Mismatched req” implies Reqs that [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figures from the paper (7 more)
Figure 4
Figure 4. Figure 4: The figure shows the Autonomous vehicle (AV) stack (abstraction from [ [PITH_FULL_IMAGE:figures/full_fig_p005_4.png]
Figure 5
Figure 5. Figure 5: LLM aided AV navigation using a supervisory monitor. The whole architecture focuses on the EGO [PITH_FULL_IMAGE:figures/full_fig_p006_5.png]
Figure 6
Figure 6. Figure 6: SSuperLLM simulation process. 5.1 Rules for the LLM Refer to [PITH_FULL_IMAGE:figures/full_fig_p007_6.png]
Figure 7
Figure 7. Figure 7: Simulation with LLM call period at 0.5 s. The LLM Supervisory control successfully manages the task. [PITH_FULL_IMAGE:figures/full_fig_p009_7.png]
Figure 8
Figure 8. Figure 8: LLM call period at 2 s. As expected, the LLM Supervisory control due to very low supervision frequency is [PITH_FULL_IMAGE:figures/full_fig_p010_8.png]
Figure 9
Figure 9. Figure 9: The System engineer of the future as imagined by AI. [PITH_FULL_IMAGE:figures/full_fig_p012_9.png]
Figure 10
Figure 10. Figure 10: LQR vs PID block diagram. A, B and C are the State, Input-to-state and State-to-output matrices correspondingly. The "System Input" is the reference(ref), where for Section 5.2 are the vehicle’s lateral (Y ) and yaw position (Ψ) (c.f. equation (8)). References [1] Nic…

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Reference graph

Works this paper leans on

29 extracted references · 24 canonical work pages

  1. [1]

    Waymo’s safety methodologies and safety readiness determinations.arXiv preprint arXiv:2011.00054, 2020

    Nick Webb, Dan Smith, Christopher Ludwick, Trent Victor, Qi Hommes, Francesca Favaro, George Ivanov, and Tom Daniel. Waymo’s safety methodologies and safety readiness determinations.arXiv preprint arXiv:2011.00054, 2020

  2. [2]

    Framework for a conflict typology including contributing factors for use in ads safety evaluation

    Kristofer D Kusano, John M Scanlon, Mattias Brännström, Johan Engström, and Trent Victor. Framework for a conflict typology including contributing factors for use in ads safety evaluation. In 27th International Technical Conference on the Enhanced Safety of Vehicles (ESV) National Highway Traffic Safety Administration, number 23-0328, 2023

  3. [3]

    Hierarchical model-based imitation learning for planning in autonomous driving

    Eli Bronstein, Mark Palatucci, Dominik Notz, Brandyn White, Alex Kuefler, Yiren Lu, Supratik Paul, Payam Nikdel, Paul Mougin, Hongge Chen, et al. Hierarchical model-based imitation learning for planning in autonomous driving. In 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 8652–8659. IEEE, 2022

  4. [4]

    Efficient information fusion and trajectory aggregation for behavior prediction.URL https://arxiv

    B Varadarajan, A Hefny, A Srivastava, KS Refaat, N Nayakanti, A Cornman, K Chen, B Douillard, CP Lam, D Anguelov, et al. Efficient information fusion and trajectory aggregation for behavior prediction.URL https://arxiv. org/abs/2111.14973, 2021

  5. [5]

    Probabilistic prediction of vehicle semantic intention and motion

    Yeping Hu, Wei Zhan, and Masayoshi Tomizuka. Probabilistic prediction of vehicle semantic intention and motion. In 2018 IEEE Intelligent Vehicles Symposium (IV), pages 307–313. IEEE, 2018

  6. [6]

    Embedding synthetic off-policy experience for autonomous driving via zero-shot curricula

    Eli Bronstein, Sirish Srinivasan, Supratik Paul, Aman Sinha, Matthew O’Kelly, Payam Nikdel, and Shimon Whiteson. Embedding synthetic off-policy experience for autonomous driving via zero-shot curricula. In Conference on Robot Learning, pages 188–198. PMLR, 2023

  7. [7]

    Systems engineering for its handbook - section 3 what is systems engineering?, 2023

    Federal Highway Administration US Department of Transportation. Systems engineering for its handbook - section 3 what is systems engineering?, 2023. 14 SSuperLLM

  8. [8]

    Safe by design autonomous driving systems

    Marius Bozga and Joseph Sifakis. Safe by design autonomous driving systems. arXiv preprint arXiv:2405.11995, 2024

Show all 29 references
  1. [9]

    Vehicle dynamics and suspension design using systems engineering

    Georgios Gatos, Spyridon Karakostas, Andreas Agiotis, and Diomidis Katzourakis. Vehicle dynamics and suspension design using systems engineering. In2024 32nd Mediterranean Conference on Control and Automation (MED), pages 328–333. IEEE, 2024

  2. [10]

    A survey of algorithms for black-box safety validation of cyber-physical systems

    Anthony Corso, Robert Moss, Mark Koren, Ritchie Lee, and Mykel Kochenderfer. A survey of algorithms for black-box safety validation of cyber-physical systems. Journal of Artificial Intelligence Research, 72:377–428, 2021

  3. [11]

    Trustworthy autonomous system development

    Joseph Sifakis and David Harel. Trustworthy autonomous system development. ACM Transactions on Embedded Computing Systems, 22(3):1–24, 2023

  4. [12]

    Driving with llms: Fusing object-level vector modality for explainable autonomous driving

    Long Chen, Oleg Sinavski, Jan Hünermann, Alice Karnsund, Andrew James Willmott, Danny Birch, Daniel Maund, and Jamie Shotton. Driving with llms: Fusing object-level vector modality for explainable autonomous driving. In 2024 IEEE International Conference on Robotics and Automa...

  5. [13]

    Advancing requirements engineering through generative ai: Assessing the role of llms

    Chetan Arora, John Grundy, and Mohamed Abdelrazek. Advancing requirements engineering through generative ai: Assessing the role of llms. In Generative AI for Effective Software Development, pages 129–148. Springer, 2024

  6. [14]

    Requirements engineering and large language models: Insights from a panel

    Markus Borg. Requirements engineering and large language models: Insights from a panel. IEEE Software, 41(2):6–10, 2024

  7. [15]

    Normative requirements operational- ization with large language models

    Nick Feng, Lina Marsso, Sinem Getir Yaman, Isobel Standen, Yesugen Baatartogtokh, Reem Ayad, Victória Oldem- burgo de Mello, Beverley Townsend, Hanne Bartels, Ana Cavalcanti, et al. Normative requirements operational- ization with large language models. In 2024 IEEE 32nd Inter...

  8. [16]

    Lessons from the use of natural language inference (nli) in requirements engineering tasks

    Mohamad Fazelnia, Viktoria Koscinski, Spencer Herzog, and Mehdi Mirakhorli. Lessons from the use of natural language inference (nli) in requirements engineering tasks. arXiv preprint arXiv:2405.05135, 2024

  9. [17]

    Sae levels of driving automation ™ refined for clarity and international audience

    I SAE. Sae levels of driving automation ™ refined for clarity and international audience. https://www.sae.org/blog/sae-j3016-update, 2021

  10. [18]

    Motion planning constraints for autonomous vehicles, January 25 2024

    Diomidis Katzourakis, John P Alsterda, Rami Y Hindiyeh, Robert Chen, and Carson Schultz. Motion planning constraints for autonomous vehicles, January 25 2024. US Patent App. 17/894,812

  11. [19]

    Autonomous systems–an architectural characterization

    Joseph Sifakis. Autonomous systems–an architectural characterization. Models, Languages, and Tools for Concurrent and Distributed Programming: Essays Dedicated to Rocco De Nicola on the Occasion of His 65th Birthday, pages 388–410, 2019

  12. [20]

    A review of motion planning techniques for automated vehicles

    David González, Joshué Pérez, Vicente Milanés, and Fawzi Nashashibi. A review of motion planning techniques for automated vehicles. IEEE Transactions on intelligent transportation systems, 17(4):1135–1145, 2015

  13. [21]

    Active suspension system with energy storage device, October 27 2020

    Diomidis Katzourakis, Christopher L Porritt, Johannes A Huennekens, Huibert Mees, and Paul J Keas. Active suspension system with energy storage device, October 27 2020. US Patent 10,814,690

  14. [22]

    Steer-by-wire system with multiple steering actuators, September 29 2020

    Diomidis Katzourakis, Huibert Mees, and Paul W Choin. Steer-by-wire system with multiple steering actuators, September 29 2020. US Patent 10,787,192

  15. [23]

    Interactive motion planning for autonomous vehicles with joint optimization

    Yuxiao Chen, Sushant Veer, Peter Karkus, and Marco Pavone. Interactive motion planning for autonomous vehicles with joint optimization. arXiv preprint arXiv:2310.18301, 2023

  16. [24]

    Council post: Safety of the intended functionality (sotif) for autonomous driv- ing

    Shaoshan Liu. Council post: Safety of the intended functionality (sotif) for autonomous driv- ing. https://www.forbes.com/sites/forbestechcouncil/2022/09/23/safety-of-the-intended-functionality-sotif-for- autonomous-driving/, 2022

  17. [25]

    Iso 26262-1:2018, road vehicles — functional safety, part 1: V ocabulary

    ISO. Iso 26262-1:2018, road vehicles — functional safety, part 1: V ocabulary. https://www.iso.org/standard/68383.html, 2018

  18. [26]

    A survey on the explainability of supervised machine learning

    Nadia Burkart and Marco F Huber. A survey on the explainability of supervised machine learning. Journal of Artificial Intelligence Research, 70:245–317, 2021

  19. [27]

    Driving simulator parameteriza- tion using double-lane change steering metrics as recorded on five modern cars

    Diomidis Katzourakis, Joost CF de Winter, Stefan de Groot, and Riender Happee. Driving simulator parameteriza- tion using double-lane change steering metrics as recorded on five modern cars. Simulation Modelling Practice and Theory, 26:96–112, 2012

  20. [28]

    Vehicle dynamics and control

    Rajesh Rajamani. Vehicle dynamics and control. Springer Science & Business Media, 2011

  21. [29]

    Dynamic programming and optimal control: Volume I, volume 4

    Dimitri Bertsekas. Dynamic programming and optimal control: Volume I, volume 4. Athena scientific, 2012. 15

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