Continual World: A Robotic Benchmark For Continual Reinforcement Learning
Not on the map. Why?
Cited by 35 in Deep reinforcement learning methods, but placed by its own abstract, which didn’t fit.
Abstract (arXiv)
Continual learning (CL) -- the ability to continuously learn, building on previously acquired knowledge -- is a natural requirement for long-lived autonomous reinforcement learning (RL) agents. While building such agents, one needs to balance opposing desiderata, such as constraints on capacity and compute, the ability to not catastrophically forget, and to exhibit positive transfer on new tasks. Understanding the right trade-off is conceptually and computationally challenging, which we argue has led the community to overly focus on catastrophic forgetting. In response to these issues, we advocate for the need to prioritize forward transfer and propose Continual World, a benchmark consisting of realistic and meaningfully diverse robotic tasks built on top of Meta-World as a testbed. Following an in-depth empirical evaluation of existing CL methods, we pinpoint their limitations and highlight unique algorithmic challenges in the RL setting. Our benchmark aims to provide a meaningful and computationally inexpensive challenge for the community and thus help better understand the performance of existing and future solutions. Information about the benchmark, including the open-source code, is available at https://sites.google.com/view/continualworld.
Key facts. Cited by 116 papers in the map (data through 14 Oct 2026). Builds on 39 of its 65 references that are in the map. First posted on arXiv 23 May 2021.
Builds on
39 of 65 references.
References · 39
- 2017Attention Is All You Needcited by 60,361
- 2014Adam: A Method for Stochastic Optimizationcited by 37,240
- 2020Language Models are Few-Shot Learnerscited by 32,419
- 2019EfficientNet: Rethinking Model Scaling for Convolutional Neural Networkscited by 6,442
- 2016Layer Normalizationcited by 5,669
- 2018Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actorcited by 4,885
- 2016Overcoming catastrophic forgetting in neural networkscited by 4,787
- 2021Zero-Shot Text-to-Image Generationcited by 4,288
- 2018Large Scale GAN Training for High Fidelity Natural Image Synthesiscited by 2,626
- 2016Progressive Neural Networkscited by 1,361
- 2018Continual Lifelong Learning with Neural Networks: A Reviewcited by 1,330
- 2018Soft Actor-Critic Algorithms and Applicationscited by 1,240
27 more
- 2019Meta-World: A Benchmark and Evaluation for Multi-Task and Meta Reinforcement Learningcited by 1,204
- 2017Memory Aware Synapses: Learning what (not) to forgetcited by 1,105
- 2018Efficient Lifelong Learning with A-GEMcited by 1,058
- 2017PackNet: Adding Multiple Tasks to a Single Network by Iterative Pruningcited by 898
- 2018Progress & Compress: A scalable framework for continual learningcited by 520
- 2019Online Continual Learning with Maximally Interfered Retrievalcited by 379
- 2017Variational Continual Learningcited by 339
- 2017CORe50: a New Dataset and Benchmark for Continuous Object Recognitioncited by 289
- 2020Towards Continual Reinforcement Learning: A Review and Perspectivescited by 274
- 2019Meta-Learning Representations for Continual Learningcited by 189
- 2019LAMOL: LAnguage MOdeling for Lifelong Language Learningcited by 160
- 2018Towards Robust Evaluations of Continual Learningcited by 148
- 2019Continual Unsupervised Representation Learningcited by 147
- 2018Multi-task Deep Reinforcement Learning with PopArtcited by 141
- 2018Don't forget, there is more than forgetting: new metrics for Continual Learningcited by 115
- 2020CausalWorld: A Robotic Manipulation Benchmark for Causal Structure and Transfer Learningcited by 109
- 2018Adapting Auxiliary Losses Using Gradient Similaritycited by 100
- 2016A Deep Hierarchical Approach to Lifelong Learning in Minecraftcited by 90
- 2017On Quadratic Penalties in Elastic Weight Consolidationcited by 55
- 2019Ray Interference: a Source of Plateaus in Deep Reinforcement Learningcited by 40
- 2019Policy Consolidation for Continual Reinforcement Learningcited by 39
- 2019Continual Learning with Adaptive Weights (CLAW)cited by 38
- 2021Continuous Coordination As a Realistic Scenario for Lifelong Learningcited by 32
- 2020Lifelong Policy Gradient Learning of Factored Policies for Faster Training Without Forgettingcited by 29
- 2019Continual Reinforcement Learning in 3D Non-stationary Environmentscited by 22
- 2020Jelly Bean World: A Testbed for Never-Ending Learningcited by 19
- 2019Adaptive Online Planning for Continual Lifelong Learningcited by 7
Built on by
Citing papers per year: 2021: 4; 2022: 14; 2023: 20; 2024: 25; 2025: 17; 2026: 36.
116 papers.
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By area:
- 2023LIBERO: Benchmarking Knowledge Transfer for Lifelong Robot Learningcited by 1,410
- 2023A Comprehensive Survey of Continual Learning: Theory, Method and Applicationcited by 872
- 2024Efficient Online Reinforcement Learning Fine-Tuning Need Not Retain Offline Datacited by 63
- 2023Continual Learning: Applications and the Road Forwardcited by 59
- 2021Powerpropagation: A sparsity inducing weight reparameterisationcited by 49
- 2021CORA: Benchmarks, Baselines, and Metrics as a Platform for Continual Reinforcement Learning Agentscited by 38
- 2021Autonomous Reinforcement Learning: Formalism and Benchmarkingcited by 33
- 2022Disentangling Transfer in Continual Reinforcement Learningcited by 33
- 2023Avalanche: A PyTorch Library for Deep Continual Learningcited by 33
- 2022vCLIMB: A Novel Video Class Incremental Learning Benchmarkcited by 28
- 2022Building a Subspace of Policies for Scalable Continual Learningcited by 28
- 2023Learning to Modulate pre-trained Models in RLcited by 28
38 more
- 2022How to Reuse and Compose Knowledge for a Lifetime of Tasks: A Survey on Continual Learning and Functional Compositioncited by 27
- 2024ODRL: A Benchmark for Off-Dynamics Reinforcement Learningcited by 25
- 2023Low-rank extended Kalman filtering for online learning of neural networks from streaming datacited by 23
- 2024Fine-tuning Reinforcement Learning Models is Secretly a Forgetting Mitigation Problemcited by 23
- 2022Lifelong Reinforcement Learning with Modulating Maskscited by 22
- 2024Online Continual Learning For Interactive Instruction Following Agentscited by 22
- 2025Robust Finetuning of Vision-Language-Action Robot Policies via Parameter Mergingcited by 22
- 2022CompoSuite: A Compositional Reinforcement Learning Benchmarkcited by 21
- 2024Retrieval-Augmented Decision Transformer: External Memory for In-context RLcited by 21
- 2024Parameter Efficient Fine-tuning via Explained Variance Adaptationcited by 20
- 2021Sequoia: A Software Framework to Unify Continual Learning Researchcited by 19
- 2022NEVIS'22: A Stream of 100 Tasks Sampled from 30 Years of Computer Vision Researchcited by 18
- 2023Is forgetting less a good inductive bias for forward transfer?cited by 18
- 2022The Effectiveness of World Models for Continual Reinforcement Learningcited by 17
- 2026Continual Learning Bench: Evaluating Frontier AI Systems in Real-World Stateful Environmentscited by 17
- 2024A Large Recurrent Action Model: xLSTM enables Fast Inference for Robotics Taskscited by 14
- 2025Skill Expansion and Composition in Parameter Spacecited by 14
- 2025Robust Gymnasium: A Unified Modular Benchmark for Robust Reinforcement Learningcited by 13
- 2025Continual Learning for Generative AI: From LLMs to MLLMs and Beyondcited by 12
- 2022Task-Agnostic Continual Reinforcement Learning: Gaining Insights and Overcoming Challengescited by 11
- 2022Beyond Supervised Continual Learning: a Reviewcited by 11
- 2023Multi-agent Continual Coordination via Progressive Task Contextualizationcited by 11
- 2023Continual Task Allocation in Meta-Policy Network via Sparse Promptingcited by 11
- 2024t-DGR: A Trajectory-Based Deep Generative Replay Method for Continual Learning in Decision Makingcited by 11
- 2025Self-Composing Policies for Scalable Continual Reinforcement Learningcited by 11
- 2025MEAL: A Benchmark for Continual Multi-Agent Reinforcement Learningcited by 11
- 2023Sharing Lifelong Reinforcement Learning Knowledge via Modulating Maskscited by 10
- 2022Reactive Exploration to Cope with Non-Stationarity in Lifelong Reinforcement Learningcited by 9
- 2024Continual Learning for Smart City: A Surveycited by 9
- 2023Towards Anytime Fine-tuning: Continually Pre-trained Language Models with Hypernetwork Promptcited by 8
- 2024A Survey Analyzing Generalization in Deep Reinforcement Learningcited by 8
- 2025Hierarchical-Task-Aware Multi-modal Mixture of Incremental LoRA Experts for Embodied Continual Learningcited by 8
- 2025Continual Reinforcement Learning by Planning with Online World Modelscited by 8
- 2023Replay-enhanced Continual Reinforcement Learningcited by 7
- 2024Can we hop in general? A discussion of benchmark selection and design using the Hopper environmentcited by 7
- 2024Stable Continual Reinforcement Learning via Diffusion-based Trajectory Replaycited by 7
- 2026CRL-VLA: Continual Vision-Language-Action Learningcited by 7
- 2026FIRE: Frobenius-Isometry Reinitialization for Balancing the Stability-Plasticity Tradeoffcited by 7
50 most cited of 116 All 116 (JSON)
- 2026EvoBelief: Falsifiable World Models for Self-Improving LLM Agents8 Oct 2026
- 2026Continual Graph Multi-Agent Reinforcement Learning7 Oct 2026
- 2026How to Find and Reuse Policies for Continuous Adaptation in Lifelong Reinforcement Learning2 Oct 2026
- 2026Continual Reinforcement Learning with Neuroevolution1 Oct 2026
- 2026Does Continual Imitation Learning Remain Grounded? A Language-Perturbed Benchmark for Robotic Task Retention30 Sep 2026
- 2026CARVE: Breaking Data Barriers in Chip Placement by Harnessing Reusable Expertise27 Sep 2026
- 2026Uncertainty-Gated Exploration Noise Suppresses Task Collapse in Online RL Fine-Tuning of a Flow-Matching Vision-Language-Action Policy23 Sep 2026
- 2026Benchmarking World Models for Continual Learning on Compositional Tasks18 Sep 2026
- 2026TraceFlow: Guiding Frozen Flow-Matching Robot Policies with Success and Failure Traces17 Sep 2026
- 2026Efficient Exploration Is Enough7 Sep 2026
- 2026CIDER: Continual Interactive Distillation for Embodied Reinforcement Learning22 Aug 2026
- 2026Beyond Forgetting: Diagnosing and Harnessing Shared Reasoning in Continual RLVR19 Aug 2026
38 more
- 2026Towards Human-like Physical Intelligence: Lifelong Vision-Language-Action Learning for Robotic Manipulation16 Jul 2026
- 2026FreqOrtho-SR: Frequency-Guided Orthogonal Expert Learning for Real-World Image Super-Resolution27 Jun 2026
- 2026Offline Multi-agent Continual Cooperation via Skill Partition and Reuse24 Jun 2026
- 2026Continual Quadruped Robots Coordination via Semantic Skill Discovery6 Jun 2026
- 2026Continual Learning Bench: Evaluating Frontier AI Systems in Real-World Stateful Environments4 Jun 2026
- 2026Local Guidance, Global Impact: Gaussian-Reshaped Trust Region Unlocks Behavior Transitions2 Jun 2026
- 2026Position: Deployed Reinforcement Learning should be Continual1 Jun 2026
- 2026Task diversity produces systematic transfer but inhibits continual reinforcement learning30 May 2026
- 2026Regime-Adaptive Continual Learning for Portfolio Management29 May 2026
- 2026Don't Forget the Critic: Value-Based Data Rehearsal for Multi-Cyclic Continual Reinforcement Learning21 May 2026
- 2026Implicit Target Shift in Online Learning: Characterization and Correction8 May 2026
- 2026SPHERE: Mitigating the Loss of Spectral Plasticity in Mixture-of-Experts for Deep Reinforcement Learning6 May 2026
- 2026Same Methods, Different Rankings: Trainable Depth as an Evaluation Variable in Continual Learning23 Apr 2026
- 2026Safe Continual Reinforcement Learning in Non-stationary Environments21 Apr 2026
- 2026Evidence of an Emergent "Self" in Continual Robot Learning25 Mar 2026
- 2026MVR: Multi-view Video Reward Shaping for Reinforcement Learning2 Mar 2026
- 2026Principled Fast and Meta Knowledge Learners for Continual Reinforcement Learning1 Mar 2026
- 2026FIRE: Frobenius-Isometry Reinitialization for Balancing the Stability-Plasticity Tradeoff8 Feb 2026
- 2026CRoSS: A Continual Robotic Simulation Suite for Scalable Reinforcement Learning with High Task Diversity and Realistic Physics Simulation4 Feb 2026
- 2026CRL-VLA: Continual Vision-Language-Action Learning3 Feb 2026
- 2026Trust Region Continual Learning as an Implicit Meta-Learner2 Feb 2026
- 2026Continual Policy Consolidation for Lifelong Robot Learning30 Jan 2026
- 2026Reinforcement Learning in the Real World: A Survey of Statistical Challenges and Future Directions21 Jan 2026
- 2026Continual-learning for Modelling Low-Resource Languages from Large Language Models9 Jan 2026
- 2025Robust Finetuning of Vision-Language-Action Robot Policies via Parameter Merging9 Dec 2025
- 2025Continual Knowledge Adaptation for Reinforcement Learning22 Oct 2025
- 2025AbideGym: Turning Static RL Worlds into Adaptive Challenges25 Sep 2025
- 2025Continual Reinforcement Learning by Planning with Online World Models12 Jul 2025
- 2025Energy-Based Transfer for Reinforcement Learning19 Jun 2025
- 2025MEAL: A Benchmark for Continual Multi-Agent Reinforcement Learning17 Jun 2025
- 2025Continual Learning for Generative AI: From LLMs to MLLMs and Beyond16 Jun 2025
- 2025Action-Adaptive Continual Learning: Enabling Policy Generalization under Dynamic Action Spaces6 Jun 2025
- 2025Hierarchical-Task-Aware Multi-modal Mixture of Incremental LoRA Experts for Embodied Continual Learning5 Jun 2025
- 2025Self-Composing Policies for Scalable Continual Reinforcement Learning4 Jun 2025
- 2025A Continual Offline Reinforcement Learning Benchmark for Navigation Tasks3 Jun 2025
- 2025The Cell Must Go On: Agar.io for Continual Reinforcement Learning23 May 2025
- 2025Efficient Continual Adaptation of Pretrained Robotic Policy with Online Meta-Learned Adapters24 Mar 2025
- 2025Mastering Continual Reinforcement Learning through Fine-Grained Sparse Network Allocation and Dormant Neuron Exploration7 Mar 2025
50 newest of 116 All 116 (JSON)
- 2024ODRL: A Benchmark for Off-Dynamics Reinforcement Learningcited by 25
- 2024Fine-tuning Reinforcement Learning Models is Secretly a Forgetting Mitigation Problemcited by 23
- 2024A Large Recurrent Action Model: xLSTM enables Fast Inference for Robotics Taskscited by 14
- 2025Robust Gymnasium: A Unified Modular Benchmark for Robust Reinforcement Learningcited by 13
- 2025Self-Composing Policies for Scalable Continual Reinforcement Learningcited by 11
- 2024A Survey Analyzing Generalization in Deep Reinforcement Learningcited by 8
- 2024Can we hop in general? A discussion of benchmark selection and design using the Hopper environmentcited by 7
- 2024Multi-granularity Knowledge Transfer for Continual Reinforcement Learningcited by 6
- 2025Continual Knowledge Adaptation for Reinforcement Learningcited by 5
- 2026Reinforcement Learning in the Real World: A Survey of Statistical Challenges and Future Directionscited by 5
- 2025Mastering Continual Reinforcement Learning through Fine-Grained Sparse Network Allocation and Dormant Neuron Explorationcited by 3
- 2026Continual Policy Consolidation for Lifelong Robot Learningcited by 3
12 most cited of 29 All 29 (JSON)
- 2026How to Find and Reuse Policies for Continuous Adaptation in Lifelong Reinforcement Learning2 Oct 2026
- 2026Continual Reinforcement Learning with Neuroevolution1 Oct 2026
- 2026CIDER: Continual Interactive Distillation for Embodied Reinforcement Learning22 Aug 2026
- 2026Local Guidance, Global Impact: Gaussian-Reshaped Trust Region Unlocks Behavior Transitions2 Jun 2026
- 2026Position: Deployed Reinforcement Learning should be Continual1 Jun 2026
- 2026Task diversity produces systematic transfer but inhibits continual reinforcement learning30 May 2026
- 2026Don't Forget the Critic: Value-Based Data Rehearsal for Multi-Cyclic Continual Reinforcement Learning21 May 2026
- 2026Safe Continual Reinforcement Learning in Non-stationary Environments21 Apr 2026
- 2026MVR: Multi-view Video Reward Shaping for Reinforcement Learning2 Mar 2026
- 2026Principled Fast and Meta Knowledge Learners for Continual Reinforcement Learning1 Mar 2026
- 2026CRoSS: A Continual Robotic Simulation Suite for Scalable Reinforcement Learning with High Task Diversity and Realistic Physics Simulation4 Feb 2026
- 2026Continual Policy Consolidation for Lifelong Robot Learning30 Jan 2026
12 newest of 29 All 29 (JSON)
- 2024Efficient Online Reinforcement Learning Fine-Tuning Need Not Retain Offline Datacited by 63
- 2024Solving Continual Offline RL through Selective Weights Activation on Aligned Spacescited by 6
- 2023OER: Offline Experience Replay for Continual Offline Reinforcement Learningcited by 4
- 2023A Real-World Quadrupedal Locomotion Benchmark for Offline Reinforcement Learningcited by 3
- 2023Learning Vision-based Robotic Manipulation Tasks Sequentially in Offline Reinforcement Learning Settingscited by 2
- 2024Continual Diffuser (CoD): Mastering Continual Offline Reinforcement Learning with Experience Rehearsalcited by 2
- 2024Hierarchical Subspaces of Policies for Continual Offline Reinforcement Learningcited by 2
- 2025A Continual Offline Reinforcement Learning Benchmark for Navigation Taskscited by 2
- 2024Continual Task Learning through Adaptive Policy Self-Compositioncited by 1
- 2026Does Continual Imitation Learning Remain Grounded? A Language-Perturbed Benchmark for Robotic Task Retentioncited by 0
- 2026Does Continual Imitation Learning Remain Grounded? A Language-Perturbed Benchmark for Robotic Task Retention30 Sep 2026
- 2025A Continual Offline Reinforcement Learning Benchmark for Navigation Tasks3 Jun 2025
- 2024Hierarchical Subspaces of Policies for Continual Offline Reinforcement Learning19 Dec 2024
- 2024Efficient Online Reinforcement Learning Fine-Tuning Need Not Retain Offline Data10 Dec 2024
- 2024Continual Task Learning through Adaptive Policy Self-Composition18 Nov 2024
- 2024Solving Continual Offline RL through Selective Weights Activation on Aligned Spaces21 Oct 2024
- 2024Continual Diffuser (CoD): Mastering Continual Offline Reinforcement Learning with Experience Rehearsal4 Sep 2024
- 2023A Real-World Quadrupedal Locomotion Benchmark for Offline Reinforcement Learning13 Sep 2023
- 2023OER: Offline Experience Replay for Continual Offline Reinforcement Learning23 May 2023
- 2023Learning Vision-based Robotic Manipulation Tasks Sequentially in Offline Reinforcement Learning Settings31 Jan 2023
- 2022The Effectiveness of World Models for Continual Reinforcement Learningcited by 17
- 2025Continual Reinforcement Learning by Planning with Online World Modelscited by 8
- 2023Continual Visual Reinforcement Learning with A Life-Long World Modelcited by 3
- 2026Benchmarking World Models for Continual Learning on Compositional Taskscited by 0
- 2026EvoBelief: Falsifiable World Models for Self-Improving LLM Agentscited by 0
- 2026EvoBelief: Falsifiable World Models for Self-Improving LLM Agents8 Oct 2026
- 2026Benchmarking World Models for Continual Learning on Compositional Tasks18 Sep 2026
- 2025Continual Reinforcement Learning by Planning with Online World Models12 Jul 2025
- 2023Continual Visual Reinforcement Learning with A Life-Long World Model12 Mar 2023
- 2022The Effectiveness of World Models for Continual Reinforcement Learning29 Nov 2022
- 2025Robust Finetuning of Vision-Language-Action Robot Policies via Parameter Mergingcited by 22
- 2026CRL-VLA: Continual Vision-Language-Action Learningcited by 7
- 2026Towards Human-like Physical Intelligence: Lifelong Vision-Language-Action Learning for Robotic Manipulationcited by 2
- 2026Uncertainty-Gated Exploration Noise Suppresses Task Collapse in Online RL Fine-Tuning of a Flow-Matching Vision-Language-Action Policycited by 0
- 2026Uncertainty-Gated Exploration Noise Suppresses Task Collapse in Online RL Fine-Tuning of a Flow-Matching Vision-Language-Action Policy23 Sep 2026
- 2026Towards Human-like Physical Intelligence: Lifelong Vision-Language-Action Learning for Robotic Manipulation16 Jul 2026
- 2026CRL-VLA: Continual Vision-Language-Action Learning3 Feb 2026
- 2025Robust Finetuning of Vision-Language-Action Robot Policies via Parameter Merging9 Dec 2025
- 2024Stable Continual Reinforcement Learning via Diffusion-based Trajectory Replaycited by 7
- 2026TraceFlow: Guiding Frozen Flow-Matching Robot Policies with Success and Failure Tracescited by 1
- 2026FreqOrtho-SR: Frequency-Guided Orthogonal Expert Learning for Real-World Image Super-Resolutioncited by 0
- 2026TraceFlow: Guiding Frozen Flow-Matching Robot Policies with Success and Failure Traces17 Sep 2026
- 2026FreqOrtho-SR: Frequency-Guided Orthogonal Expert Learning for Real-World Image Super-Resolution27 Jun 2026
- 2024Stable Continual Reinforcement Learning via Diffusion-based Trajectory Replay16 Nov 2024
- 2023LIBERO: Benchmarking Knowledge Transfer for Lifelong Robot Learningcited by 1,410
- 2023A Comprehensive Survey of Continual Learning: Theory, Method and Applicationcited by 872
- 2023Continual Learning: Applications and the Road Forwardcited by 59
- 2021Powerpropagation: A sparsity inducing weight reparameterisationcited by 49
- 2021CORA: Benchmarks, Baselines, and Metrics as a Platform for Continual Reinforcement Learning Agentscited by 38
- 2021Autonomous Reinforcement Learning: Formalism and Benchmarkingcited by 33
- 2022Disentangling Transfer in Continual Reinforcement Learningcited by 33
- 2023Avalanche: A PyTorch Library for Deep Continual Learningcited by 33
- 2022vCLIMB: A Novel Video Class Incremental Learning Benchmarkcited by 28
- 2022Building a Subspace of Policies for Scalable Continual Learningcited by 28
- 2023Learning to Modulate pre-trained Models in RLcited by 28
- 2022How to Reuse and Compose Knowledge for a Lifetime of Tasks: A Survey on Continual Learning and Functional Compositioncited by 27
12 most cited of 62 All 62 (JSON)
- 2026Continual Graph Multi-Agent Reinforcement Learning7 Oct 2026
- 2026CARVE: Breaking Data Barriers in Chip Placement by Harnessing Reusable Expertise27 Sep 2026
- 2026Efficient Exploration Is Enough7 Sep 2026
- 2026Offline Multi-agent Continual Cooperation via Skill Partition and Reuse24 Jun 2026
- 2026Continual Quadruped Robots Coordination via Semantic Skill Discovery6 Jun 2026
- 2026Continual Learning Bench: Evaluating Frontier AI Systems in Real-World Stateful Environments4 Jun 2026
- 2026Regime-Adaptive Continual Learning for Portfolio Management29 May 2026
- 2026Implicit Target Shift in Online Learning: Characterization and Correction8 May 2026
- 2026Same Methods, Different Rankings: Trainable Depth as an Evaluation Variable in Continual Learning23 Apr 2026
- 2026Evidence of an Emergent "Self" in Continual Robot Learning25 Mar 2026
- 2026FIRE: Frobenius-Isometry Reinitialization for Balancing the Stability-Plasticity Tradeoff8 Feb 2026
- 2026Trust Region Continual Learning as an Implicit Meta-Learner2 Feb 2026
12 newest of 62 All 62 (JSON)