Cryptix at SemEval-2026 Task 4: Zero-Shot Bi-Encoder Modeling for Narrative Story Similarity - A Sentence Transformer Approach

Sushmitha M, Sarath Kumar P, Thanalaxmi S, Beulah A


Abstract
This submission presents a zero-shot embedding-based approach for SemEval-2026 Task 4 on Narrative Story Similarity. The system employs the pretrained sentence-transformers/all-mpnet-base-v2 model within a bi-encoder architecture to generate 768-dimensional story embeddings. Narrative similarity is modeled using cosine similarity in embedding space for comparative prediction in Track A and representation generation in Track B. The approach does not involve task-specific fine-tuning and treats narrative comparison as a geometric proximity problem. Experimental results and error analysis highlight the strengths of pretrained semantic encoders in capturing thematic similarity, while revealing limitations in modeling deeper narrative structure and causal progression.
Anthology ID:
2026.semeval-1.168
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1282–1287
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.168/
DOI:
Bibkey:
Cite (ACL):
Sushmitha M, Sarath Kumar P, Thanalaxmi S, and Beulah A. 2026. Cryptix at SemEval-2026 Task 4: Zero-Shot Bi-Encoder Modeling for Narrative Story Similarity - A Sentence Transformer Approach. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 1282–1287, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Cryptix at SemEval-2026 Task 4: Zero-Shot Bi-Encoder Modeling for Narrative Story Similarity - A Sentence Transformer Approach (M et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.168.pdf
Supplementarymaterial:
 2026.semeval-1.168.SupplementaryMaterial.zip
Supplementarymaterial:
 2026.semeval-1.168.SupplementaryMaterial.zip