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arXiv 2310.09397cs.LGmath.AGmath.STstat.TH
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专家乘积模型的可辨识性

Identifiability of Product of Experts Models

California Institute of Technology(加州理工学院)

Spencer L. Gordon, Manav Kant, Eric Ma, Leonard J. Schulman, Andrei Staicu

AI总结:

本文研究专家乘积模型的可辨识性,证明在潜变量均匀分布时所需观测数等于参数数,任意分布时仍为线性,依赖根交错现象。

摘要:

专家乘积(PoE)是一种分层网络,其中每个节点的值是其输入值(可能取反)的AND(或乘积)。这类网络最初被引入作为一种神经网络架构,能够高效学习生成满足许多低维约束的高维数据,从而允许每个单独的专家执行简单任务。PoE在学习中已有多种应用。我们研究具有一层二元潜变量和一层在给定潜变量条件下独立同分布的二元可观测变量的专家乘积模型的可辨识性问题。此前关于识别该模型所需可观测变量数量的最佳上界是参数数量的指数级。我们证明:(a)当潜变量均匀分布时,模型在可观测变量数量等于参数数量时即可辨识(因此这是最佳可能)。(b)在潜变量任意分布的更一般情形下,模型在可观测变量数量仍与参数数量呈线性关系(且在最佳可能的2倍因子内)时即可辨识。证明依赖于某些特殊三项递推的根交错现象。

英文摘要:

Product of experts (PoE) are layered networks in which the value at each node is an AND (or product) of the values (possibly negated) at its inputs. These were introduced as a neural network architecture that can efficiently learn to generate high-dimensional data which satisfy many low-dimensional constraints -- thereby allowing each individual expert to perform a simple task. PoEs have found a variety of applications in learning. We study the problem of identifiability of a product of experts model having a layer of binary latent variables, and a layer of binary observables that are iid conditional on the latents. The previous best upper bound on the number of observables needed to identify the model was exponential in the number of parameters. We show: (a) When the latents are uniformly distributed, the model is identifiable with a number of observables equal to the number of parameters (and hence best possible). (b) In the more general case of arbitrarily distributed latents, the model is identifiable for a number of observables that is still linear in the number of parameters (and within a factor of two of best-possible). The proofs rely on root interlacing phenomena for some special three-term recurrences.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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