activity
20232026
collaborators

11 papers

math.AG2026

Smoothness criterion for Fano orbifolds and bases of Lagrangian fibrations

Zhiyu Liu

We establish a smoothness criterion for Fano varieties with quotient singularities. As an application, we show that if is a Lagrangian fibration from a compact hyper-Kähle…

stat.ML2026

One-Step Score-Based Density Ratio Estimation

Wei Chen, Qibin Zhao, John Paisley +2

Density ratio estimation (DRE) is a useful tool for quantifying discrepancies between probability distributions, but existing approaches often involve a trade-off between estimatio…

cs.LG2026

Towards Disentangled Preference Optimization Dynamics: Suppress the Loser, Preserve the Winner

Wei Chen, Yubing Wu, Junmei Yang +5

Preference optimization is widely used to align large language models (LLMs) with human preferences. However, many margin-based methods also suppress the chosen response when they…

cs.LG2026

A Minimum Variance Path Principle for Accurate and Stable Score-Based Density Ratio Estimation

Wei Chen, Jiacheng Li, Shigui Li +4

Score-based methods are powerful across machine learning, but they face a paradox: theoretically path-independent, yet practically path-dependent. We resolve this by proving that p…

stat.ML2025

Diffusion Secant Alignment for Score-Based Density Ratio Estimation

Wei Chen, Shigui Li, Jiacheng Li +6

Estimating density ratios has become increasingly important with the recent rise of score-based and diffusion-inspired methods. However, current tangent-based approaches rely on a…

cs.LG2025

Dequantified Diffusion-Schr{ö}dinger Bridge for Density Ratio Estimation

Wei Chen, Shigui Li, Jiacheng Li +3

Density ratio estimation is fundamental to tasks involving -divergences, yet existing methods often fail under significantly different distributions or inadequately overlapping…

cs.LG2024

Flexible Bayesian Last Layer Models Using Implicit Priors and Diffusion Posterior Sampling

Jian Xu, Zhiqi Lin, Shigui Li +4

Bayesian Last Layer (BLL) models focus solely on uncertainty in the output layer of neural networks, demonstrating comparable performance to more complex Bayesian models. However,…

cs.LG2024

Variational Learning of Gaussian Process Latent Variable Models through Stochastic Gradient Annealed Importance Sampling

Jian Xu, Shian Du, Junmei Yang +3

Gaussian Process Latent Variable Models (GPLVMs) have become increasingly popular for unsupervised tasks such as dimensionality reduction and missing data recovery due to their fle…

cs.LG2024

Fully Bayesian Differential Gaussian Processes through Stochastic Differential Equations

Jian Xu, Zhiqi Lin, Min Chen +3

Deep Gaussian process models typically employ discrete hierarchies, but recent advancements in differential Gaussian processes (DiffGPs) have extended these models to infinite dept…

cs.LG2023

Neural Operator Variational Inference based on Regularized Stein Discrepancy for Deep Gaussian Processes

Jian Xu, Shian Du, Junmei Yang +2

Deep Gaussian Process (DGP) models offer a powerful nonparametric approach for Bayesian inference, but exact inference is typically intractable, motivating the use of various appro…

cs.LG2023

Bayesian Gaussian Process ODEs via Double Normalizing Flows

Jian Xu, Shian Du, Junmei Yang +3

Recently, Gaussian processes have been used to model the vector field of continuous dynamical systems, referred to as GPODEs, which are characterized by a probabilistic ODE equatio…