Research map / Learning theory and algorithms / Combinatorial and search optimization
Classical and HTN planning
Designs heuristics, compilations and symbolic search for numeric and hierarchical planning.
145 accepted papers at ICML, NeurIPS, ICLR, CVPR and AAAI (2016–2026) · an approach in Combinatorial and search optimization, keyword cluster “planning · search algorithm · tree search”
State History Tried Preprints Who Export
Where it stands
Not enough benchmark data Fewer than four papers report the same benchmark, so there is no record to follow.
33 papers in 2023–24 and 24 in 2025–26 (at ICML, NeurIPS, ICLR, CVPR and AAAI); its share of the topic shrank, from 9.5% to 6.6%.
How this is decided
A benchmark is tracked when at least four papers of this approach report their own method on the same dataset and metric in at least two different years. Its record is the best number reported up to 2024 compared with the best reported in 2025–26: still improving means at least 1% better, flat means at most 0.2% better with at least two papers from 2025–26 trying. Numbers on a different scale from the rest (a fraction among percentages) and far outliers are left out. Results come from different papers with different setups, so they are signals, not head-to-head comparisons. The share of papers is counted at ICML, NeurIPS, ICLR, CVPR and AAAI.
How it got here
Most cited paper of each year
- 2016 · Surprise-Triggered Reformulation of Design Goals (AAAI 2016 · 21 citations)
- 2017 · Non-Deterministic Planning with Temporally Extended Goals: LTL over Finite and Infinite Traces (AAAI 2017 · 74 citations)
- 2018 · An AI Planning Solution to Scenario Generation for Enterprise Risk Management (AAAI 2018 · 45 citations)
- 2019 · Learning Features and Abstract Actions for Computing Generalized Plans (AAAI 2019 · 42 citations)
- 2020 · HDDL: An Extension to PDDL for Expressing Hierarchical Planning Problems (AAAI 2020 · 73 citations)
- 2021 · BT Expansion: a Sound and Complete Algorithm for Behavior Planning of Intelligent Robots with Behavior Trees (AAAI 2021 · 22 citations)
- 2022 · Making Translations to Classical Planning Competitive with Other HTN Planners (AAAI 2022 · 10 citations)
- 2023 · TransPath: Learning Heuristics for Grid-Based Pathfinding via Transformers (AAAI 2023 · 22 citations)
- 2024 · Abstract Action Scheduling for Optimal Temporal Planning via OMT (AAAI 2024 · 6 citations)
- 2025 · An Automatic Sound and Complete Abstraction Method for Generalized Planning with Baggable Types (AAAI 2025 · 1 citation)
- 2026 · MeshA*: Efficient Path Planning with Motion Primitives (AAAI 2026 · 2 citations)
Earliest papers here
- Surprise-Triggered Reformulation of Design Goals (AAAI 2016 · 21 citations)
- Verifying ConGolog Programs on Bounded Situation Calculus Theories (AAAI 2016 · 18 citations)
- Metaphysics of Planning Domain Descriptions (AAAI 2016 · 16 citations)
What has been tried
117 papers here report 953 measured changes (a component added, removed or swapped, compared with a baseline): helped 61%, no clear effect 8%, hurt 22%, mixed 8%. Papers mostly publish changes that helped, so "helped" is over-represented.
Ablations in recent papers
| What was changed | Measured on | Result | Effect | Paper |
|---|---|---|---|---|
| remove the optimization-before-first-plan improvement | IPC-14 and benchmark set · coverage (optimally solved instances) | 147 -> 145 | Hurt | Abstract Action Scheduling for Optimal Temporal Planning via OMT (AAAI 2024 · 6 citations) |
| Reduce the number of feasibility and buyability samples | 25-molecule subsample · SSP | Hurt | Retro-fallback: retrosynthetic planning in an uncertain world (ICLR 2024 · 4 citations) | |
| Add synthetic distance D to Retro* guidance | USPTO-190, N=500 · solve rate (%) | 35.8 -> 37.4 | Helped | Double-Ended Synthesis Planning with Goal-Constrained Bidirectional Search (NeurIPS 2024 · 3 citations) |
| Add achiever-based optimization to the basic NTCORE compilation | All domains (512 instances) · coverage | 289 -> 351; 21.4% | Helped | Dealing with Numeric and Metric Time Constraints in PDDL3 via Compilation to Numeric Planning (AAAI 2024 · 2 citations) |
| Use numeric variables in iPDB patterns rather than ignoring all numeric variables | Numeric planning benchmarks · state expansions | Helped | PDBs Go Numeric: Pattern-Database Heuristics for Simple Numeric Planning (AAAI 2025 · 1 citation) | |
| add sub-goal decomposition to System-1.5 | Maze Navigation · plan validity | 50.0 -> 70.4 | Helped | System 1.x: Learning to Balance Fast and Slow Planning with Language Models (ICLR 2025 · 1 citation) |
| Improve the dependency graph | Hard-to-ground domains · coverage | 262 -> 212 | Hurt | Optimizing the Optimization of Planning Domains by Automatic Action Schema Splitting (AAAI 2024 · 1 citation) |
| Replace the k-medians-with-penalties subroutine with k-medians | Ant U-Maze and Fetch-Reach · average planning time | Hurt | Discovering Options That Minimize Average Planning Time (AAAI 2025 · 0 citations) | |
| Replace the original captime-doubling condition with the refined condition | Log-Laplace utility; other utility functions show similar improvement · optimality guarantee and time per configuration | Helped | Utilitarian Algorithm Configuration for Infinite Parameter Spaces (ICLR 2025 · 0 citations) | |
| Remove the location-x-y-is-visited variables | Visit-All · river measure | 1 to 2 | Hurt | Novelty vs. Potential Heuristics: A Comparison of Hardness Measures for Satisficing Planning (AAAI 2024 · 0 citations) |
| Vary the mirror descent stepsize | 7-card 4-hint Hanabi · expected return | Mixed | The Update-Equivalence Framework for Decision-Time Planning (ICLR 2024 · 0 citations) | |
| add stochastic additional planning steps during fine-tuning | Associative Recall, larger inputs · accuracy | Helped | DNCs Require More Planning Steps (ICML 2024 · 0 citations) |
Recent preprints
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Who publishes on it
Institutions on the most papers of this approach since 2023 (of 57 papers; from OpenAlex and the papers' affiliations).
- Australian National University · 6 papers
- Technion - Israel Institute of Technology · 4 papers
- Fondazione Bruno Kessler · 3 papers
- University of Basel · 3 papers
- Technion · 2 papers
- University of Trento · 2 papers
- Washington University in St. Louis · 2 papers
- Universit `a degli Studi di Brescia · 2 papers
- University of Huddersfield · 2 papers
- Universiteit van Amsterdam · 2 papers
Use it
Download BibTeX of 40 key papersOpen the topic in the interactive map
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Related approaches
Same keyword cluster
- Heuristic and local search algorithms (147 papers)
- Monte Carlo tree search (55 papers)
- Search for program synthesis (38 papers)
Elsewhere in the topic
- Logic and answer set programming theory (150 papers)
- Unsupervised neural combinatorial optimization (113 papers)
- Constrained neural network optimization (111 papers)
- Decision-focused optimization (97 papers)
- Multi-objective optimization (93 papers)
- Structure and complexity of constraint reasoning (92 papers)
- Predict-then-optimize learning (89 papers)
- SAT and model counting solvers (89 papers)
Benchmark numbers, ablations and baseline numbers are extracted by AI from each paper's full text and can be wrong; the paper is the authority. Data: results index of 2026-11-02, citation counts from OpenAlex (2026-10-09).