On the Mechanisms of Collaborative Learning in VAE Recommenders

Fuente: arXiv
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Autori principali: Vuong, Tung-Long, Monteil, Julien, Dang, Hien, Vaskovych, Volodymyr, Le, Trung, Nguyen, Vu
Natura: Preprint
Pubblicazione: 2025
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author Vuong, Tung-Long
Monteil, Julien
Dang, Hien
Vaskovych, Volodymyr
Le, Trung
Nguyen, Vu
author_facet Vuong, Tung-Long
Monteil, Julien
Dang, Hien
Vaskovych, Volodymyr
Le, Trung
Nguyen, Vu
contents Variational Autoencoders (VAEs) are a powerful alternative to matrix factorization for recommendation. A common technique in VAE-based collaborative filtering (CF) consists in applying binary input masking to user interaction vectors, which improves performance but remains underexplored theoretically. In this work, we analyze how collaboration arises in VAE-based CF and show it is governed by \emph{latent proximity}: we derive a latent sharing radius that informs when an SGD update on one user strictly reduces the loss on another user, with influence decaying as the latent Wasserstein distance increases. We further study the induced geometry: with clean inputs, VAE-based CF primarily exploits \emph{local} collaboration between input-similar users and under-utilizes \emph{global} collaboration between far-but-related users. We compare two mechanisms that encourage \emph{global} mixing and characterize their trade-offs: \ding{172} $β$-KL regularization directly tightens the information bottleneck, promoting posterior overlap but risking representational collapse if too large; \ding{173} input masking induces stochastic \emph{geometric} contractions and expansions, which can bring distant users onto the same latent neighborhood but also introduce neighborhood drift. To preserve user identity while enabling global consistency, we propose an anchor regularizer that aligns user posteriors with item embeddings, stabilizing users under masking and facilitating signal sharing across related items. Our analyses are validated on the Netflix, MovieLens-20M, and Million Song datasets. We also successfully deployed our proposed algorithm on an Amazon streaming platform following a successful online experiment.
format Preprint
id arxiv_https___arxiv_org_abs_2511_06781
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Mechanisms of Collaborative Learning in VAE Recommenders
Vuong, Tung-Long
Monteil, Julien
Dang, Hien
Vaskovych, Volodymyr
Le, Trung
Nguyen, Vu
Machine Learning
Artificial Intelligence
Variational Autoencoders (VAEs) are a powerful alternative to matrix factorization for recommendation. A common technique in VAE-based collaborative filtering (CF) consists in applying binary input masking to user interaction vectors, which improves performance but remains underexplored theoretically. In this work, we analyze how collaboration arises in VAE-based CF and show it is governed by \emph{latent proximity}: we derive a latent sharing radius that informs when an SGD update on one user strictly reduces the loss on another user, with influence decaying as the latent Wasserstein distance increases. We further study the induced geometry: with clean inputs, VAE-based CF primarily exploits \emph{local} collaboration between input-similar users and under-utilizes \emph{global} collaboration between far-but-related users. We compare two mechanisms that encourage \emph{global} mixing and characterize their trade-offs: \ding{172} $β$-KL regularization directly tightens the information bottleneck, promoting posterior overlap but risking representational collapse if too large; \ding{173} input masking induces stochastic \emph{geometric} contractions and expansions, which can bring distant users onto the same latent neighborhood but also introduce neighborhood drift. To preserve user identity while enabling global consistency, we propose an anchor regularizer that aligns user posteriors with item embeddings, stabilizing users under masking and facilitating signal sharing across related items. Our analyses are validated on the Netflix, MovieLens-20M, and Million Song datasets. We also successfully deployed our proposed algorithm on an Amazon streaming platform following a successful online experiment.
title On the Mechanisms of Collaborative Learning in VAE Recommenders
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2511.06781