Exact Tensorization Formulas for Jensen-Shannon Divergence Contraction: The Z-Channel and Binary Erasure Channel
Abstract
Closed-form formulas for JSD contraction coefficients of tensor-product channels. Key results:- Edge Reduction Theorem with full proof- Z-channel: coefficient depends on support set asymmetry, not Hamming distance- Chernoff–JSD correspondence for boundary-optimizer channels Note (March 2026): By the general identity η_f(W) = η_χ²(W) for all f-divergences (Ordentlich-Polyanskiy; Polyanskiy-Wu Theorem 33.6), all formulas in this work simultaneously give η_χ² for the same tensor-product channels. The results are not JSD-specific.
Fields of Study & Subjects
Holomorphic and Operator Theory
Spectral Theory in Mathematical Physics
Algebraic and Geometric Analysis
Publication details
- Journal / source
- Zenodo (CERN European Organization for Nuclear Research)
- Publication date
- 14 January 2026
- Language
- EN
- Document type
- Preprint