Panagiotis Lymperopoulos

dblp:160/6413 · DBLP profile ↗
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4ranked-venue papers
3as first author
4since 2021 · last 2025
0000-0002-5193-8168ORCID · reported

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 4 · 3 first-author · 4 since 2021Theory of computation · 1 · 1 first-author · 1 since 2021
YearPublicationVenuePosition
2025 Tools in the Loop: Quantifying Uncertainty of LLM Question Answering Systems That Use Tools
Panagiotis Lymperopoulos, Vasanth Sarathy
AAMAS1
2025 Act-to-Ground: A Framework for Symbol Grounding in Planning Domains
abstract
Neurosymbolic decision-making agents inherit many of the critical transparency and interpretability benefits of planning-based symbolic agents but also face one of their central challenges: the Symbol Grounding Problem (SGP). Grounding hand-crafted symbolic planning domains to percepts typically requires training models with extensive annotated data which hinders their applicability to broader problems. In this work we propose Act-to-Ground (A2G), a framework for training grounding models for symbolic planners with weak supervision obtained through environment interaction or demonstrations. We first cast the grounding problem as an inference problem and 1) use satisfiability-based planning to provide weak supervision to the grounding model by exploiting knowledge already built into the planning domain, 2) propose an MCMC sampler that enables sampling weak labels for grounding planners, 3) improve neurosymbolic grounding performance via a score-matching objective and 4) propose a learnability condition for learning grounding models for planners.
Panagiotis Lymperopoulos, Liping Liu 0001
NeSy1
2024 Graph Pruning for Enumeration of Minimal Unsatisfiable Subsets
abstract
Finding Minimal Unsatisfiable Subsets (MUSes) of boolean constraints is a common problem in infeasibility analysis of over-constrained systems. However, because of the exponential search space of the problem, enumerating MUSes is extremely time-consuming in real applications. In this work, we propose to prune formulas using a learned model to speed up MUS enumeration. We represent formulas as graphs and then develop a graph-based learning model to predict which part of the formula should be pruned. Importantly, the training of our model does not require labeled data. It does not even require training data from the target application because it extrapolates to data with different distributions. In our experiments we combine our model with existing MUS enumerators and validate its effectiveness in multiple benchmarks including a set of real-world problems outside our training distribution. The experiment results show that our method significantly accelerates MUS enumeration on average on these benchmark problems.
Panagiotis Lymperopoulos, Liping Liu 0001
AISTATS1
2024 A neurosymbolic cognitive architecture framework for handling novelties in open worlds
Shivam Goel, Panagiotis Lymperopoulos, Ravenna Thielstrom, Evan A. Krause, Patrick Feeney, Pierrick Lorang, Sarah Schneider, Eric J. Kildebeck, Stephen A. Goss, Michael C. Hughes, Liping Liu 0001, Jivko Sinapov, Matthias Scheutz
Artif. Intell.2