Divergence and Deformed Exponential Family
Hiroshi Matsuzoe, Asuka Takatsu
TL;DR
The paper generalizes information-geometric foundations by introducing the $(h,\tau)$-divergence and $(h,\tau)$-exponential families. It establishes a sufficient condition under which the induced metric and flat connection form a Hessian structure, and it frames a corresponding canonical divergence and Pythagorean relation. It then develops the theory of identically repeatable deformed exponential families and proves a law of large numbers for $(h,\tau)$-dependent sequences, including explicit constructions and probabilistic bounds. These results broaden the scope of information geometry to deformed entropies and nonstandard divergences, enabling generalized statistical modeling and convergence analyses beyond the classical KL/exponential-family setting.
Abstract
The Kullback--Leibler divergence together with exponential families establishes the foundation of information geometry and is widely generalized. Among the generalization, we focus on the $(h,τ)$-divergence and $(h,τ)$-exponential families. We present a sufficient condition for the $(h,τ)$-divergence to induce a Hessian structure on an $(h,τ)$-exponential family. We also define the $(h,τ)$-dependence of random variables and prove a kind of the law of large numbers.
