KITE: Kernelized and Information Theoretic Exemplars for In-Context Learning

Vaibhav Singh, Soumya Suvra Ghosal, Kapu Nirmal Joshua, Soumyabrata Pal, Sayak Ray Chowdhury


Abstract
In-context learning (ICL) has emerged as a powerful paradigm for adapting large language models (LLMs) to new, data-scarce tasks using only a few carefully selected task-specific examples embedded in the prompt. However, given the limited context size of LLMs, a fundamental question arises: Which examples should be selected to maximize performance on a given user query? While nearest-neighbor-based methods have been widely adopted for this purpose, they suffer from well-known drawbacks in high-dimensional embedding spaces, including poor generalization and limited diversity. In this work, we study example selection in ICL from a principled, information-theoretic perspective. We frame the example selection task as a query-specific high-dimensional optimization problem: selecting a subset of exemplars from a larger example bank to minimize prediction error for a given query. To solve this, we first derive a principled surrogate objective that is approximately submodular, enabling the use of a greedy algorithm with an approximation guarantee. We further enhance our method by introducing an optimal design-based regularizer to encourage diversity in the selected examples. Empirically, we demonstrate significant improvements over standard retrieval methods across a suite of classification tasks, highlighting the benefits of structure-aware, diverse example selection for ICL in real-world, label-scarce scenarios.
Anthology ID:
2026.findings-emnlp.1667
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
35547–35568
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URL:
https://aclanthology.org/2026.findings-emnlp.1667/
DOI:
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Cite (ACL):
Vaibhav Singh, Soumya Suvra Ghosal, Kapu Nirmal Joshua, Soumyabrata Pal, and Sayak Ray Chowdhury. 2026. KITE: Kernelized and Information Theoretic Exemplars for In-Context Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 35547–35568, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
KITE: Kernelized and Information Theoretic Exemplars for In-Context Learning (Singh et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1667.pdf