@article{Gouda_Bujdosó_Hassaan_2022, title={Scaling Subgraph Matching by Improving Ullmann Algorithm}, volume={41}, url={https://www.cai.sk/ojs/index.php/cai/article/view/2022_4_1002}, DOI={10.31577/cai_2022_4_1002}, abstractNote={<p>Graphs are widely used to model complicated data semantics in many application domains. Subgraph isomorphism checking (an NP-complete problem) is a regular operation with this kind of data. In this paper, we propose an improvement of Ullmann algorithm, a well-known subgraph isomorphism checker. Our new algorithm is called Ullmann-ONL. It utilizes a new search ordering and L-levels of vertex neighborhoods (NL) to confine the search space of Ullmann algorithm. Our performance study shows that Ullmann-ONL outperforms previously proposed algorithms with a wide margin.</p>}, number={4}, journal={COMPUTING AND INFORMATICS}, author={Gouda, Karam and Bujdosó, Gyöngyi and Hassaan, Mosab}, year={2022}, month={Nov.}, pages={1002–1024} }