Reinforcement learning (RL) is a branch of machine learning in which an agent learns to make sequential decisions by interacting with an environment and receiving feedback in the form of rewards or penalties.
Machine Learning
A Markov Decision Process (MDP) is a mathematical framework for modeling sequential decision-making in stochastic environments.
Machine LearningMathematics
Microduck is a small biped robot developed by Pollen Robotics, the robotics team within Hugging Face.
Open Source AIRobot Hardware
Misha Laskin (also published as Michael Laskin) is an AI researcher and entrepreneur best known for his work on reinforcement learning and for co-founding Reflection AI
People
Model soups is a weight-averaging technique (a form of model merging) that combines several independently fine-tuned neural networks into a single model by averaging their parameters.
Machine Learning
MonoRace is an onboard perception and control system for autonomous racing drones, developed at the Micro Air Vehicle Laboratory (MAVLab) of Delft University of Technology (TU Delft) in the Netherlands.
Computer VisionEmbodied AI
Monte Carlo Tree Search (MCTS) is a heuristic search algorithm for sequential decision-making that finds strong actions by running many simulated playthroughs of a problem and aggregating their outcomes into a…
AI in GamingAlgorithms
MuJoCo (short for Multi-Joint dynamics with Contact) is an open-source physics simulator designed for fast and accurate simulation of articulated mechanical systems with rich contact interactions.
Open Source AIRobotics
MuZero is a model-based reinforcement learning algorithm developed by DeepMind that reached superhuman play in Go, chess, and shogi and set a new state of the art on the 57-game Atari benchmark without being…
AI ModelsGoogle DeepMind
A multi-armed bandit is a sequential decision problem in which a learner repeatedly picks one action from a fixed set, receives a random reward for that action only, and tries to accumulate as much reward as…
AlgorithmsMachine Learning
NVIDIA COMPASS is a framework and trained model for cross-embodiment robot navigation. Its name expands to Cross-Embodiment Mobility Policy via Residual RL and Skill Synthesis.
AI ModelsEmbodied AI
NVIDIA Isaac Lab is an open-source, GPU-accelerated framework for robot learning that trains robot control policies at scale by running thousands of physics simulations in parallel on GPUs.
NVIDIARobotics
A Nash equilibrium is a combination of strategies, one for each player in a game, such that no player can raise their own payoff by changing strategy alone while everyone else keeps theirs unchanged.
AlgorithmsComputer Science
Online learning is a machine learning paradigm in which a model receives data sequentially, one example or one mini-batch at a time, and updates its parameters immediately after each observation rather than…
Machine Learning
OpenAI Baselines is a collection of open-source, high-quality reference implementations of reinforcement learning (RL) algorithms released by OpenAI.
Open Source AIOpenAI
OpenAI Five was a reinforcement learning system developed by OpenAI to play the competitive multiplayer video game Dota 2 at a professional level.
AI in GamingArtificial Intelligence
PROWL-1 is a training framework from the AI lab Odyssey in which a reinforcement learning agent is paid to break a world model.
Machine LearningTraining & Optimization
Pieter Abbeel (born 1977) is a Belgian-American computer scientist and a professor of electrical engineering and computer sciences at the University of California, Berkeley, where he directs the Berkeley Robot…
PeopleRobotics
Pluribus is an artificial intelligence program that defeated elite human professionals at six-player no-limit Texas hold'em, the most popular form of poker played by people.
AI in GamingMeta AI
In reinforcement learning (RL), a policy is the function that maps an agent's observed state to the action it takes, defining the agent's complete strategy of behavior.
Machine Learning
Policy gradient methods are a family of reinforcement learning algorithms that directly parameterise the agent's policy and optimise it by stochastic gradient ascent on the expected return.
Machine LearningTraining & Optimization
A process reward model (PRM), also called a process-supervised reward model or step-level verifier, is a learned scoring model that evaluates the correctness or quality of each intermediate step in a large…
AI SafetyMachine Learning
Proximal Policy Optimization (PPO) is an on-policy policy gradient reinforcement learning algorithm that stabilizes training by clipping the policy update so the new policy stays close ("proximal") to the old…
Machine LearningTraining & Optimization
The Q-function, also called the action-value function or state-action value function and written…
Machine Learning
Q-learning is a model-free, off-policy reinforcement learning algorithm that learns the value of taking a given action in a given state by iteratively updating an action-value function Q(s, a), the expected…
Machine Learning
Quiet-STaR is a self-supervised training method that teaches a large language model to generate short, token-level internal "thoughts," or rationales, that help it predict the text that follows
Machine Learning
RAGEN-2 is a 2026 research paper and public code extension for diagnosing and mitigating reasoning collapse during reinforcement learning of multi-turn large language model agents.
AI AgentsAI Research
Reinforcement Learning from AI Feedback (RLAIF) is a family of alignment techniques for large language models in which the preference labels used to fine-tune a model are produced by another AI system
AI SafetyMachine Learning
RLOO (REINFORCE Leave-One-Out) is an online reinforcement learning algorithm for aligning large language models with reward signals such as those derived from human preferences.
AI AlignmentTraining & Optimization
Reinforcement Learning with Verifiable Rewards (RLVR) is a post-training paradigm for large language models in which the reward signal comes from a deterministic
AI InferenceReasoning Models
A random policy is a reinforcement learning policy that chooses actions from a fixed probability distribution, most commonly the uniform distribution, independent of the current state and of any learned value…
Machine Learning
ReST (Reinforced Self-Training) is a family of self-training algorithms for large language models that improve a model by fine-tuning it on its own filtered outputs instead of on additional human-written data.
Machine Learning
Recursive reward modeling (RRM) is a proposed approach to the scalable oversight problem in AI alignment
AI AlignmentAI Safety
Reflex is a research framework for visually reactive whole-body control of a Unitree G1 humanoid.
AI ResearchRobotics
Reinforcement learning (RL) is a branch of machine learning in which an agent learns to make decisions by taking actions in an environment to maximize a cumulative reward signal, discovering good behavior…
Artificial IntelligenceDeep Learning
A replay buffer (also called an experience replay buffer or replay memory) is a fixed-size memory that stores an off-policy reinforcement learning agent's past transitions, each a tuple of state, action…
Deep LearningMachine Learning
In reinforcement learning, the return…
Machine Learning
In reinforcement learning (RL), a reward is a scalar feedback signal that an environment sends to an agent after each action, quantifying how desirable that action's outcome was
Machine Learning
A reward model (RM) is a model trained to score the outputs of another AI system, producing a scalar estimate of how good a candidate response is according to some standard, most often human preference.
Reward hacking (also called specification gaming) is a failure mode in artificial intelligence in which a system maximizes its given objective or reward signal through unintended shortcuts, exploits, or…
AI AlignmentAI Safety
RewardBench is a benchmark and public leaderboard for evaluating reward models, the scoring functions that sit at the center of reinforcement learning from human feedback (RLHF).
AI BenchmarksModel Evaluation
Richard Stuart Sutton (born 1957 or 1958) is a Canadian-American computer scientist regarded as one of the founders of modern computational reinforcement learning, and a co-recipient, with Andrew G. Barto
AI ResearchPeople
River AI (legally River AI Inc.) is an American artificial intelligence company based in Palo Alto, California, founded in 2026 by Igor Babuschkin, a co-founder of xAI.
AI CompaniesAI Infrastructure
Robot learning studies how robots acquire or improve behavior from data and experience.
Deep LearningMachine Learning
Robotics models are machine learning systems that give robots the ability to perceive their surroundings, plan actions, and execute motor control.
AI Models
SARSA (State-Action-Reward-State-Action) is an on-policy temporal-difference (TD) control algorithm that learns the action-value function Q^pi(s, a) of the policy an agent is actually following
Machine Learning
SONIC, short for Supersizing mOtion tracking for Natural humanoId Control, is a physics-based whole-body motion tracking and control system developed by Nvidia.
Humanoid RobotsNVIDIA
SPADE, short for Self-Play in Adaptive Synthetic Executable Environments, is a reinforcement-learning framework in which one language model alternates between designing executable training environments and…
AI AgentsLarge Language Models
STaR (Self-Taught Reasoner) is a self-training method that teaches a large language model to reason by having it generate its own chain-of-thought rationales, keeping only the rationales that lead to correct…
Machine Learning
Selective Language Modeling (SLM) is a pretraining objective for language models that applies the training loss to only a chosen subset of tokens rather than to every token in the corpus.
Machine Learning
Sergey Levine is a computer scientist, associate professor of electrical engineering and computer sciences at the University of California, Berkeley, and a co-founder of Physical Intelligence
PeopleRobotics
Sim-to-real transfer (also written as sim2real) is the process of training a policy, controller, or perception model inside a physics simulator and deploying it on a physical robot in the real world without…
Robotics
Simulation in artificial intelligence and robotics is the use of computational physics, rendering, and procedural environments to recreate a synthetic version of a physical or virtual world inside which AI…
Embodied AIPhysical AI
SkyRL is an open-source reinforcement learning (RL) library for post-training large language models and multi-turn agents.
Developer ToolsOpen Source AI
Soft Actor-Critic (SAC) is an off-policy, maximum-entropy deep reinforcement learning algorithm that trains a stochastic actor-critic to maximize expected reward plus the entropy of its own policy, so the…
AlgorithmsDeep Learning
Sparse upcycling is a technique for building a sparsely activated mixture of experts (MoE) model by initializing it from an already trained dense Transformer checkpoint
Machine Learning
Specification gaming is the phenomenon in which an optimizer satisfies the literal specification of an objective without producing the outcome that the designer actually wanted.
AI AlignmentAI Safety
Spinning Up in Deep RL is a free, open-source educational resource produced by OpenAI to make deep reinforcement learning (deep RL) easier to learn.
OpenAI
In reinforcement learning (RL), a state is a complete description of the environment at a particular point in time, containing all the information an agent needs to choose its next action.
Machine Learning
The state-action value function, written Q^π(s, a) and also called the action-value function or Q-function, gives the expected discounted return an agent obtains by taking action a in state s and thereafter…
Machine Learning