BanditRLlib
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Canonical multi-axis taxonomy

Bandit Taxonomy

Reader-facing taxonomy for BanditRLlib. It separates mathematical settings, objectives, algorithm families, cross-cutting guarantee properties, RL/application bridges, and unresolved aliases. Classification is distinct from the Bound & Source Atlas and from Frontier open problems.

66canonical entries
26represented or mentioned
36missing explicit topic
3aliases needing source disambiguation

Do not flatten settings, objectives, and methods

BAI and regret minimization are objectives; Thompson sampling and GP-UCB are methods; LLM is an application bridge. A result becomes comparable only after the environment/action class, feedback, objective, probability mode, parameters, computation/oracle assumptions and theorem source are fixed.

Ambiguous acronyms stay quarantined. OMDP, SLB and Transform require a cited source before canonicalization. In particular, SLB is used in the literature for both stochastic linear bandits and safe linear bandits, so the bare acronym is not merged into either node.

Foundations & objectives · 8

P0 · objective · case-covered

Best-arm identification (BAI)

Pure exploration, fixed-confidence or fixed-budget, with sample complexity/error probability rather than cumulative regret.

Aliases. BAI, Best-1-Arm

Technique map. Elimination / sequential testing

P0 · objective · family-covered

Regret minimization

Cumulative learning objective; keep separate from pure exploration/identification.

Aliases. RM, regret

P1 · objective · missing-topic

Single-objective bandits

Scalar reward/regret objective; useful mainly as the parent contrast for multi-objective/Pareto bandits.

Aliases. Single-Objective

Technique map. Scalarization / Pareto / multi-objective selection

P1 · objective · missing-topic

Threshold / thresholding bandits

Identify/classify arms relative to a threshold; distinct from BAI despite sharing pure-exploration tools.

Aliases. Threshold Bandits

Technique map. Elimination / sequential testing

P1 · objective · missing-topic

Top-m / combinatorial pure exploration

Identify a subset or combinatorial optimum; important bridge between BAI and structured bandits.

Technique map. Elimination / sequential testing

Feedback, noise & robustness · 10

P0 · setting · family-covered

Stochastic bandits

Stationary stochastic rewards; parent of many finite-arm and structured stochastic settings.

Technique map. Confidence sets → optimism → regret

P1 · setting · missing-topic

Dueling / preference bandits

Pairwise/comparative feedback rather than scalar reward observations.

Aliases. Dueling bandits, preference bandits

Technique map. Pairwise preference / dueling reductions

P1 · setting · missing-topic

Missing / censored outcome bandits

Selected rewards may be unobserved or censored; missingness mechanism must be part of the model contract.

Aliases. Missing Outcome Bandits, censored bandits

Technique map. Robust estimation / truncation / robust confidence

P1 · objective · missing-topic

Risk-sensitive / CVaR / survival bandits

Optimize tail risk, safety probability, ruin/survival or other distributional criteria beyond expected reward.

Aliases. risk-aware bandits

Technique map. Primal–dual / Lagrangian resource control

Structured action/reward models · 15

P0 · setting · missing-topic

Bandit convex optimization

Bandit feedback for convex losses over convex action domains; now mature enough for a dedicated extended route.

Aliases. Convex Bandits, BCO

Technique map. Bandit convex smoothing / gradient estimation

P0 · setting · topic-covered

Combinatorial bandits

Combinatorial action sets, often with semi-bandit/full-bandit feedback; oracle/relaxation and computational hardness must be tracked.

Aliases. Combinatorial Bandits

Technique map. Combinatorial oracle / relaxation / semi-bandit estimation

P0 · setting · family-covered

Contextual bandits

Actions are chosen conditional on observed contexts; realizability and policy/function classes must be explicit.

Aliases. Contextual Bandits

Technique map. Posterior sampling / probability matching

P0 · setting · topic-covered

Lipschitz / continuum-armed bandits

Metric action spaces with Lipschitz reward structure; zooming/near-optimality dimension is a major proof route.

Aliases. Lipschitz Bandits, zooming

Technique map. Zooming / metric localization

P1 · setting · missing-topic

Factored bandits

Reward/action model factorizes across components; distinguish from generic combinatorial and low-rank models.

Aliases. Factored Bandits

Technique map. Low-dimensional / sparse / factorized structure

P1 · setting · missing-topic

Graph-feedback / graphical bandits

Feedback or reward structure is governed by a graph; distinguish feedback graphs from graph-structured reward models.

Aliases. Graphical Bandits, graph feedback

Technique map. Feedback-graph / partial-monitoring information structure

P1 · setting · topic-covered

Matrix / low-rank / tensor bandits

Structured high-dimensional reward parameter; rank, action factorization and observation model must be explicit.

Aliases. Matrix Bandits

Technique map. Low-dimensional / sparse / factorized structure

P1 · setting · missing-topic

Multinomial-logit (MNL) / assortment bandits

If 'multinomial' means MNL choice/assortment bandits, use this canonical label; a generic multinomial reward law is only a reward-distribution specialization.

Aliases. Multinomial Bandits, MNL bandits

Technique map. Low-dimensional / sparse / factorized structure

P1 · setting · missing-topic

Sparse / high-dimensional bandits

Linear/GLM/kernel problems with sparsity or intrinsic-dimension structure; useful cross-pollination route to compressed sensing.

Technique map. Low-dimensional / sparse / factorized structure

Time, availability & resources · 11

P0 · setting · family-covered

Dynamic / nonstationary bandits

Reward model changes over time; variation, switch, drift and comparator budgets must not be conflated.

Aliases. Dynamic Bandits, nonstationary bandits

Technique map. Change detection / windows / variation-budget adaptation

P1 · setting · missing-topic

Ballooning / growing-arm bandits

The available arm set grows over time; the user's 'Bolling' label is normalized here to Ballooning.

Aliases. Bolling Bandits, Ballooning Bandits, BL-MAB

Technique map. Change detection / windows / variation-budget adaptation

P1 · setting · missing-topic

Multi-fidelity bandits

Queries trade fidelity/cost against information; connect to multi-fidelity Bayesian optimization.

Aliases. Multi-Fidelity

Technique map. Primal–dual / Lagrangian resource control

P1 · setting · missing-topic

Safe bandits

Constraint violations themselves must be controlled; safety semantics differ from generic budget constraints.

Aliases. Safe Bandits

Technique map. Primal–dual / Lagrangian resource control

Multiple agents / distributed learning · 5

P1 · setting · mentioned-not-indexed

Fairness / incentives / strategic bandits

Learning interacts with fairness or strategic agent constraints; link to the economics/agents textbook routes.

Aliases. incentivized exploration

P1 · setting · missing-topic

Private / JDP bandits

Privacy constraints change achievable regret and proof techniques; currently has explicit COLT open-problem history.

Aliases. differentially private bandits, JDP contextual bandits

Technique map. Privacy accounting / randomized perturbation

Algorithm families · 5

P0 · method · chapter-covered

EXP3 / FTRL / mirror-descent methods

Optimization-based adversarial-bandit methods and best-of-both-worlds variants.

Aliases. EXP3, Tsallis-INF

Technique map. Exponential weights / FTRL / mirror descent

P0 · method · topic-and-chapter-covered

Thompson sampling / posterior sampling

Bayesian/posterior-sampling method; keep as method, not setting.

Aliases. Tompson Sampling, Thompson Sample, TS

Technique map. Posterior sampling / probability matching

P0 · method · chapter-covered

UCB / optimism methods

Confidence-bound method family crossing stochastic, linear, kernel and RL settings.

Aliases. UCB

P1 · method · missing-topic

Elimination / successive rejects / racing

Core method family for pure exploration and confidence-based regret algorithms.

Technique map. Elimination / sequential testing

Oracle, computation & quantum access · 1

P0 · setting · cross-library-route

Quantum bandits

Bandit models with genuinely quantum access or quantum-valued environments. Keep reward-oracle QMAB/QLB, quantum-state/observable bandits, and quantum contextual models separate; classical bandit theorems do not transfer without an explicit oracle/statistical bridge.

Aliases. Quantum MAB, QMAB, Quantum Linear Bandits, QLB, quantum reward-oracle bandits, quantum-state bandits

Technique map. Quantum mean estimation / quantum testing / quantum design

RL & application bridges · 8

P1 · setting · missing-topic

Online / adversarial MDP

MDP with online/adversarial costs or changing environments; do not abbreviate as OMDP without expansion.

Aliases. online MDP

Technique map. Bellman recursion + optimistic bonuses

P1 · setting · missing-topic

Partially observable MDP (POMDP)

Partial observability changes planning and learning complexity.

Aliases. POMDP

Technique map. Belief-state / memory representation

P2 · application-bridge · missing-topic

Bandits for LLM / language-model systems

Application bridge for preference learning, routing, inference-time allocation, evaluation or adaptation; map each paper back to a precise mathematical setting.

Aliases. LLM

Technique map. Preference / routing / allocation reductions for LLM systems

Aliases needing source disambiguation · 3

P1 · ambiguous · quarantine

SLB

Ambiguous acronym in the literature: it is used for stochastic linear bandits and also safe linear bandits. Preserve the label for discovery, but require a cited source before mapping a contribution to one canonical setting.

Aliases. SLB

P2 · ambiguous · quarantine

OMDP

Do not canonicalize until a source defines whether this means online MDP, observable MDP, or another model.

Aliases. OMDP

P2 · ambiguous · quarantine

Transform

No stable canonical bandit setting was identified from the bare label; retain as an alias quarantine entry until a paper/source is supplied.

Aliases. Transform

Contributor rule

Adding a setting name is not enough. A substantive update must use the repository contribution contract, connect the affected reader/route/progress surfaces, and classify its Lean Graph and Functor Hypergraph delta.

Read the contributor/Codex publication contract →