Ivan Silajev published a paper showing TF-IDF and BM25 are exact Kullback-Leibler divergences. The work covers the BM25 variant with the plus 1 IDF correction. It also discusses the original BM25 formulation without that correction. The paper provides a unified probabilistic framework for both methods. It clarifies what TF-IDF and BM25 measure. It enables theoretical comparison with other information retrieval methods. The paper is five pages long. It was submitted to arXiv on 12 September 2026.