activity
20202025
most citedGraph InfoClust: Leveraging cluster-level node information for unsupervised graph representation learning

48 citations · 81 across the 10 of their papers we have counts for

collaborators

11 papers

cs.CL2025

BYOKG-RAG: Multi-Strategy Graph Retrieval for Knowledge Graph Question Answering

Costas Mavromatis, Soji Adeshina, Vassilis N. Ioannidis +6

Knowledge graph question answering (KGQA) presents significant challenges due to the structural and semantic variations across input graphs. Existing works rely on Large Language M…

cs.CL2024★ 16 cited

GNN-RAG: Graph Neural Retrieval for Large Language Model Reasoning

Costas Mavromatis, George Karypis

Knowledge Graphs (KGs) represent human-crafted factual knowledge in the form of triplets (head, relation, tail), which collectively form a graph. Question Answering over KGs (KGQA)…

cs.CL2024★ 2 cited

Pack of LLMs: Model Fusion at Test-Time via Perplexity Optimization

Costas Mavromatis, Petros Karypis, George Karypis

Fusing knowledge from multiple Large Language Models (LLMs) can combine their diverse strengths to achieve improved performance on a given task. However, current fusion approaches…

cs.CL2024

SemPool: Simple, robust, and interpretable KG pooling for enhancing language models

Costas Mavromatis, Petros Karypis, George Karypis

Knowledge Graph (KG) powered question answering (QA) performs complex reasoning over language semantics as well as knowledge facts. Graph Neural Networks (GNNs) learn to aggregate…

cs.CL2023★ 3 cited

Which Examples to Annotate for In-Context Learning? Towards Effective and Efficient Selection

Costas Mavromatis, Balasubramaniam Srinivasan, Zhengyuan Shen +4

Large Language Models (LLMs) can adapt to new tasks via in-context learning (ICL). ICL is efficient as it does not require any parameter updates to the trained LLM, but only few an…

cs.LG2023★ 1 cited

Train Your Own GNN Teacher: Graph-Aware Distillation on Textual Graphs

Costas Mavromatis, Vassilis N. Ioannidis, Shen Wang +6

How can we learn effective node representations on textual graphs? Graph Neural Networks (GNNs) that use Language Models (LMs) to encode textual information of graphs achieve state…

cs.CL2022★ 1 cited

ReaRev: Adaptive Reasoning for Question Answering over Knowledge Graphs

Costas Mavromatis, George Karypis

Knowledge Graph Question Answering (KGQA) involves retrieving entities as answers from a Knowledge Graph (KG) using natural language queries. The challenge is to learn to reason ov…

cs.CL2021★ 8 cited

TempoQR: Temporal Question Reasoning over Knowledge Graphs

Costas Mavromatis, Prasanna Lakkur Subramanyam, Vassilis N. Ioannidis +5

Knowledge Graph Question Answering (KGQA) involves retrieving facts from a Knowledge Graph (KG) using natural language queries. A KG is a curated set of facts consisting of entitie…

cs.LG2021★ 2 cited

HeMI: Multi-view Embedding in Heterogeneous Graphs

Costas Mavromatis, George Karypis

Many real-world graphs involve different types of nodes and relations between nodes, being heterogeneous by nature. The representation learning of heterogeneous graphs (HGs) embeds…

cs.SI2021

Unveiling Anomalous Edges and Nominal Connectivity of Attributed Networks

Konstantinos D. Polyzos, Costas Mavromatis, Vassilis N. Ioannidis +1

Uncovering anomalies in attributed networks has recently gained popularity due to its importance in unveiling outliers and flagging adversarial behavior in a gamut of data and netw…

cs.LG2020★ 48 cited

Graph InfoClust: Leveraging cluster-level node information for unsupervised graph representation learning

Costas Mavromatis, George Karypis

Unsupervised (or self-supervised) graph representation learning is essential to facilitate various graph data mining tasks when external supervision is unavailable. The challenge i…