activity
20232026
most citedMixDec Sampling: A Soft Link-based Sampling Method of Graph Neural Network for Recommendation

2 citations · 4 across the 14 of their papers we have counts for

collaborators

17 papers

math.AG2026

Birational maps of moduli spaces of stable sheaves on a K3 surface induced by Fourier-Mukai transforms

Kota Yoshioka

We shall study birational maps of moduli spaces of stable sheaves on a K3 surface with Picard number 1 induced by Fourier-Mukai transforms.

cs.LG2026

Optimal Multi-Reward Reinforcement Learning

Zijun Chen, Zihan Zhang

We study an unknown-transition finite-horizon Markov decision process (MDP) with a finite collection of known reward functions . The goal is to output an…

cs.LG2026

Asymptotically Optimal Regret for Reinforcement Learning without Horizon Dependence

Runlong Zhou, Zihan Zhang, Maryam Fazel +1

We study horizon-free regret minimization for finite-horizon time-homogeneous tabular Markov decision processes with states, actions, horizon , and per-trajectory total…

cs.LG2026

Tighter Regret Bounds for Contextual Action-Set Reinforcement Learning

Zijun Chen, Zihan Zhang

We study episodic reinforcement learning with fixed reward and transition functions, but with episode-dependent admissible action sets that are observed at the start of each episod…

cs.LG2026

Frozen Policy Iteration: Computationally Efficient RL under Linear Realizability for Deterministic Dynamics

Yijing Ke, Zihan Zhang, Ruosong Wang

We study computationally and statistically efficient reinforcement learning under the linear realizability assumption, where any policy's -function is linear in a given st…

cs.RO2026

Safe-SDL:Establishing Safety Boundaries and Control Mechanisms for AI-Driven Self-Driving Laboratories

Zihan Zhang, Haohui Que, Junhan Chang +3

The emergence of Self-Driving Laboratories (SDLs) transforms scientific discovery methodology by integrating AI with robotic automation to create closed-loop experimental systems c…

cs.CL2026

TodoEvolve: Learning to Architect Agent Planning Systems

Jiaxi Liu, Yanzuo Jiang, Guibin Zhang +5

Planning has become a central capability for contemporary agent systems in navigating complex, long-horizon tasks, yet existing approaches predominantly rely on fixed, hand-crafted…

cs.LG2026

Online Learning for Uninformed Markov Games: Empirical Nash-Value Regret and Non-Stationarity Adaptation

Junyan Liu, Haipeng Luo, Zihan Zhang +1

We study online learning in two-player uninformed Markov games, where the opponent's actions and policies are unobserved. In this setting, Tian et al. (2021) show that achieving no…

cs.LG2026

Unregularized Linear Convergence in Zero-Sum Game from Preference Feedback

Shulun Chen, Runlong Zhou, Zihan Zhang +2

Aligning large language models (LLMs) with human preferences has proven effective for enhancing model capabilities, yet standard preference modeling using the Bradley-Terry model a…

cs.LG2025

Sharp Gap-Dependent Variance-Aware Regret Bounds for Tabular MDPs

Shulun Chen, Runlong Zhou, Zihan Zhang +2

We consider the gap-dependent regret bounds for episodic MDPs. We show that the Monotonic Value Propagation (MVP) algorithm achieves a variance-aware gap-dependent regret bound of…

cs.LG2025

Understanding the Performance Gap in Preference Learning: A Dichotomy of RLHF and DPO

Ruizhe Shi, Minhak Song, Runlong Zhou +3

We present a fine-grained theoretical analysis of the performance gap between two-stage reinforcement learning from human feedback~(RLHF) and direct preference optimization~(DPO).…

cs.IR2025★ 2 cited

MixDec Sampling: A Soft Link-based Sampling Method of Graph Neural Network for Recommendation

Xiangjin Xie, Yuxin Chen, Ruipeng Wang +8

Graph neural networks have been widely used in recent recommender systems, where negative sampling plays an important role. Existing negative sampling methods restrict the relation…

cs.LG2024

Anytime Acceleration of Gradient Descent

Zihan Zhang, Jason D. Lee, Simon S. Du +1

This work investigates stepsize-based acceleration of gradient descent with {\em anytime} convergence guarantees. For smooth (non-strongly) convex optimization, we propose a stepsi…

cs.LG2024

Achieving Tractable Minimax Optimal Regret in Average Reward MDPs

Victor Boone, Zihan Zhang

In recent years, significant attention has been directed towards learning average-reward Markov Decision Processes (MDPs). However, existing algorithms either suffer from sub-optim…

cs.LG2024

Horizon-Free Regret for Linear Markov Decision Processes

Zihan Zhang, Jason D. Lee, Yuxin Chen +1

A recent line of works showed regret bounds in reinforcement learning (RL) can be (nearly) independent of planning horizon, a.k.a.~the horizon-free bounds. However, these regret bo…

cs.RO2024★ 1 cited

We Choose to Go to Space: Agent-driven Human and Multi-Robot Collaboration in Microgravity

Miao Xin, Zhongrui You, Zihan Zhang +7

We present SpaceAgents-1, a system for learning human and multi-robot collaboration (HMRC) strategies under microgravity conditions. Future space exploration requires humans to wor…

cs.LG2023★ 1 cited

Optimal Multi-Distribution Learning

Zihan Zhang, Wenhao Zhan, Yuxin Chen +2

Multi-distribution learning (MDL), which seeks to learn a shared model that minimizes the worst-case risk across distinct data distributions, has emerged as a unified framework…