Typed states for the displayed outbound observations.
Source: paper_references, paper_reference_links, observed 2026-08-07T15:04:01.363663Z
Paper Citation Record · LEDGER
As of 7 August 2026, this Paper Citation Record lists 49 of 49 outbound references and 16 inbound Pith citation observations for arXiv:2505.16640.
A citation records a reference. It does not transfer a finding from one paper to another.
Typed states for the displayed outbound observations.
Source: paper_references, paper_reference_links, observed 2026-08-07T15:04:01.363663Z
One-hop event checks from named stored sources.
Source: scholarly_work_events, retraction_status_cache, observed 2026-08-07T06:34:17.273281+00:00
Pith citing papers itemized under the disclosed page cap.
Source: paper_references, paper_reference_links, observed 2026-08-06T00:41:30.013412Z
A source-named dated measurement, never combined with another source.
Source: arxiv_reference, observed 2026-08-05T02:28:24.338817Z
49 of 49 outbound references displayed
External citation measurements
0
arxiv_reference, observed 2026-08-05T02:28:24.338817Z
Observation bcd4ab95-aa11-431d-8cda-622ee9854b89 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization $\pi_0$: A Vision-Language-Action Flow Model for General Robot Control
Reference 1
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 0da2bfcf-eea7-4170-ac2a-cc5786227889 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization RT-2: Vision-Language-Action Models Transfer Web Knowledge to Robotic Control
Reference 2
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation caf71072-ee0c-47d9-b2ed-9d727d5ea4dc · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization PaLI-X: On Scaling up a Multilingual Vision and Language Model
Reference 3
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation d6f1e72d-c833-452f-9469-6cc5f7bd23a6 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Targeted Backdoor Attacks on Deep Learning Systems Using Data Poisoning
Reference 4
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 1876874c-b6bf-4318-9732-b2ae36fe931b · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Manipulation facing threats: Evaluating physical vulnerabilities in end-to-end vision language action models, 2024
Reference 5
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 8dad1db0-5b45-49d9-9e85-76110536429b · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Open X-Embodiment: Robotic Learning Datasets and RT-X Models
Reference 6
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation b8759b5b-c83c-4f82-b525-f719cab5894d · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization PaLM-E: An Embodied Multimodal Language Model
Reference 7
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 5d5141ef-26ee-4ae7-867e-9ef64731601a · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Bridge Data: Boosting Generalization of Robotic Skills with Cross-Domain Datasets
Reference 8
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation fa4830ef-b66a-4cd3-8da9-0cd4010c3092 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization RH20T: A Comprehensive Robotic Dataset for Learning Diverse Skills in One-Shot
Reference 9
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 700e6b9b-3c97-4f82-b910-fe39f8679dfb · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Towards artificial general intelligence via a multimodal foundation model
Reference 10
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 1e9a8a95-a170-49b1-b0d3-a81e517bf936 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Foundation models in robotics: 11 Applications, challenges, and the future
Reference 11
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 1babccfb-e2e0-42ae-8095-26a5f72b24e7 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Robustness of learning from task instructions, 2023
Reference 12
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 7c544824-a1e1-437e-8832-4d7414e69c4c · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Badnets: Evaluating backdooring attacks on deep neural networks
Reference 13
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 415a7332-e1c7-4c9e-bba3-8a5e67b1e9b3 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Task-oriented Robotic Manipulation with Vision Language Models
Reference 14
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 0900040f-a961-4724-a701-f732cf3c5436 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Benchmarking Vision, Language, & Action Models on Robotic Learning Tasks
Reference 15
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 34ba4f44-e389-4a18-b088-ed238258cc45 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization The franka emika robot: A reference platform for robotics research and education
Reference 16
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 57c5ae31-779c-4aaa-8a3c-dd2ea56b6545 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization OpenVLA: An Open-Source Vision-Language-Action Model
Reference 17
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 524a9c13-ddf4-4caa-905b-d93d6a0c7822 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Prompt Infection: LLM-to-LLM Prompt Injection within Multi-Agent Systems
Reference 18
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 1b16272f-66ac-4e50-a783-e906c8945fd4 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Vision-Language Foundation Models as Effective Robot Imitators
Reference 19
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 39a6566d-fffd-4e5d-a300-6cddec5e9fe4 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Backdoor learning: A survey
Reference 20
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 9bacaf4a-2350-44d8-966c-dc4cb939dd20 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Vl-trojan: Multimodal instruction backdoor attacks against autoregressive visual language models
Reference 21
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 615a5c13-2769-45a7-90b7-6efda48fc19f · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Revisiting Backdoor Attacks against Large Vision-Language Models from Domain Shift
Reference 22
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation fa7bef9c-947b-4452-8b7a-787d949aa26a · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Flow Matching for Generative Modeling
Reference 23
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 2f3c0a21-023d-421b-a14a-80048aff993f · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Libero: Benchmarking knowledge transfer for lifelong robot learning
Reference 24
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation dc243864-cd91-4efc-9c81-290fc99b70c8 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization A Survey of Attacks on Large Vision-Language Models: Resources, Advances, and Future Trends
Reference 25
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 3269f884-48f7-41ae-ac89-246019cf1dac · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Robomamba: Efficient vision- language-action model for robotic reasoning and manipulation
Reference 26
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ec1ad98f-36f4-4d05-bb88-d24723940128 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Unraveling and Mitigating Safety Alignment Degradation of Vision-Language Models
Reference 27
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e8caa19c-53de-4456-8fd3-a3b8c322e301 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Friendly noise against adversarial noise: a powerful defense against data poisoning attack
Reference 28
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation c7dbf271-07ba-4189-9537-d477baeae198 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Safety Alignment for Vision Language Models
Reference 29
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ac2637ee-58ea-4bbd-8dc2-b760e3c7c66d · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Trojvlm: Backdoor attack against vision language models
Reference 30
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation f2704314-95ca-42b1-9d9c-5ad8d84bda0d · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization A survey on vision-language-action models for embodied ai, 2025
Reference 31
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation ba2fa290-d44a-49bc-aab9-5a80cbf82ff6 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Autonomous Workflow for Multimodal Fine-Grained Training Assistants Towards Mixed Reality
Reference 32
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 60cc8b52-68a4-4666-9617-aa661226dc9e · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization SpatialVLA: Exploring Spatial Representations for Visual-Language-Action Model
Reference 33
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation cbdcede5-0c6f-473b-a374-a3c41c6ad53a · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Certified defenses for data poisoning attacks
Reference 34
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation b4baf0c2-5b84-42fa-bdc9-284192defb98 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Octo: An Open-Source Generalist Robot Policy
Reference 35
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e2bb5bd9-fa9b-417b-9d4d-5bdc2155af29 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Llama 2: Open Foundation and Fine-Tuned Chat Models
Reference 36
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 5bc2d187-336b-479d-bbe8-a09b8aaa988f · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Exploring the adversarial vulnerabilities of vision-language-action models in robotics, 2025
Reference 37
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 3b51d84d-c8a8-459e-953b-640e488347c7 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Invisible black-box backdoor attack against deep cross-modal hashing retrieval
Reference 38
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation e6a0e3b1-ca48-4bdf-94ea-3d618716c3cf · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Trojanrobot: Physical-world backdoor attacks against vlm-based robotic manipulation
Reference 39
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 391293fe-2ed3-40e4-a08e-054d6f949b27 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization InstructTA: Instruction-Tuned Targeted Attack for Large Vision-Language Models
Reference 40
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 4cd00f41-373c-4196-b055-82c48e1cd5e2 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Adversarial attacks on multimodal agents
Reference 41
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation d82ac1d1-7e89-4d3d-98e7-8fdd42d13fa1 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Dissecting Adversarial Robustness of Multimodal LM Agents
Reference 42
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 93a583b2-3863-44a0-a7a1-5a71a206e686 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Adversarial t-shirt! evading person detectors in a physical world,
Reference 43
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 0772a19f-d6a7-4ed8-9e35-e47d5d8c28e8 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Compression-resistant backdoor attack against deep neural networks
Reference 44
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 247a933f-e852-4bce-9e46-a762242dacaf · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Visual Adversarial Attack on Vision-Language Models for Autonomous Driving
Reference 45
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 9fbc2bca-cdcd-453c-87f9-3ff02b1be280 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Gadei: On scale-up training as a service for deep learning
Reference 46
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 672997b2-8d01-46af-b5d2-e2b5ead04af4 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Badcm: Invisible backdoor attack against cross-modal learning
Reference 47
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation b9b58612-b4bb-4b69-a49d-d0ceda8543f4 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Revisiting the Adversarial Robustness of Vision Language Models: a Multimodal Perspective
Reference 48
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ce99ff9e-fb9f-4503-8784-e1aa91e03ff7 · outbound
BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization Adversarial T-shirt! Evading Person Detectors in A Physical World
Reference 2020
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 5c633738-e24e-4bed-a8b9-d4bf043d77e8 · inbound
ANNIE: Be Careful of Your Robots BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 96
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 8445cced-2873-4095-b6c0-17dfe7baeed9 · inbound
State Backdoor: Towards Stealthy Real-world Poisoning Attack on Vision-Language-Action Model in State Space BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 15
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 2ddeba9e-d2a1-4461-b893-8df29db754f0 · inbound
When control meets large language models: From words to dynamics BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 209
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 4b4aeceb-78b5-4045-838f-0e0af595e582 · inbound
SlowBA: An efficiency backdoor attack towards VLM-based GUI agents BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 71
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e87022be-e0b8-4987-a14e-599b551b4c92 · inbound
TRAP: Hijacking VLA CoT-Reasoning via Adversarial Patches BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 19
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation f3a24cca-98f1-4f9b-bf74-c7cb9431a1f3 · inbound
SABER: A Stealthy Agentic Black-Box Attack Framework for Vision-Language-Action Models BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 26
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation d5bd4e92-2269-4073-96d1-69c7c13de471 · inbound
FlowHijack: A Dynamics-Aware Backdoor Attack on Flow-Matching Vision-Language-Action Models BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 44
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 221b7a16-6038-42fd-9a90-802cc48f4b81 · inbound
TRAP: Tail-aware Ranking Attack for World-Model Planning BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 50
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation ac84a3ec-5b62-4b10-9e0c-e41c5fef3c6a · inbound
Securing Computer-Use Agents: A Unified Architecture-Lifecycle Framework for Deployment-Grounded Reliability BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 157
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 35ecd89a-7daf-4a65-b36a-ee6655a4bc4c · inbound
Towards Backdoor-Based Ownership Verification for Vision-Language-Action Models BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 22
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation fd788293-a181-497c-9838-7ed4afb7e6ac · inbound
VLA-Hijack: A Transferable Patch Attack against Vision-Language-Action Models via Visual Proprioception Hijacking BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 36
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation e70e0a67-6834-4e9b-bb40-d070aae3053d · inbound
ReasonBreak: Probing Vulnerabilities in Reasoning-Enabled Vision-Language-Action Models for Autonomous Driving BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 55
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation 700ce834-2bac-42a9-a358-ec7a2c49600f · inbound
Targeting World Models to Compromise Robot Learning Pipelines BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 48
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-07T06:34:17.273281+00:00.
Observation e64dd588-8f01-44fb-b2d0-6c771f528b27 · inbound
!Imperio, smolVLA: The Implications of Data Poisoning on Open Source Robotics BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 18
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation a1f0309d-e2ca-4514-8d06-6260c49e2391 · inbound
ActFovea: Runtime Safeguarding for VLA Policies via Spatiotemporal Visual-Action Consistency BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 9
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation a83ab1fa-054d-4420-abac-7bec8235f93e · inbound
VLAGuard: A Framework for Evaluating and Mitigating Physical Attention Hijacking in Vision-Language-Action Robots within Wireless Sensor Networks BadVLA: Towards Backdoor Attacks on Vision-Language-Action Models via Objective-Decoupled Optimization
Reference 39
Source-reported events for the cited work
Unavailable: canonical work link unavailable.