← Search

Zhenmei Shi

21 accepted papers

2025

Beyond Linear Approximations: A Novel Pruning Approach for Attention Matrix

ICLR 2025poster

Large Language Models (LLMs) have shown immense potential in enhancing various aspects of our daily lives, from conversational AI to search and AI assistants. However, their growing capabilities come at the cost of extremely large model sizes, making deployment on edge devices challenging due to mem…

Cited by 4SourcePDFScholar
2025

Bypassing the Exponential Dependency: Looped Transformers Efficiently Learn In-context by Multi-step Gradient Descent

AISTATS 2025poster

In-context learning has been recognized as a key factor in the success of Large Language Models (LLMs). It refers to the model's ability to learn patterns on the fly from provided in-context examples in the prompt during inference. Previous studies have demonstrated that the Transformer architecture…

Cited by 0SourceScholar
2025

Circuit Complexity Bounds for RoPE-based Transformer Architecture

EMNLP 2025

Characterizing the expressive power of the Transformer architecture is critical to understanding its capacity limits and scaling law. Recent works provide the circuit complexity bounds to Transformer-like architecture. On the other hand, position embedding has emerged as a crucial technique in moder

Cited by 0SourcePDFScholar
2025

Conv-Basis: A New Paradigm for Efficient Attention Inference and Gradient Computation in Transformers

EMNLP 2025

The self-attention mechanism is key to the success of transformers in recent large language models (LLMs). However, the quadratic computational cost, O(n 2 ) , with respect to the input sequence length n poses a significant obstacle to further improvement and scalability in longer contexts.In this w

Cited by 0SourcePDFScholar
2025

Dissecting Submission Limit in Desk-Rejections: A Mathematical Analysis of Fairness in AI Conference Policies

ICML 2025poster

As AI research surges in both impact and volume, conferences have imposed submission limits to maintain paper quality and alleviate organizational pressure. In this work, we examine the fairness of desk-rejection systems under submission limits and reveal that existing practices can result in subst…

Cited by 5SourcePDFScholar
2025

Fourier Circuits in Neural Networks and Transformers: A Case Study of Modular Arithmetic with Multiple Inputs

AISTATS 2025poster

In the evolving landscape of machine learning, a pivotal challenge lies in deciphering the internal representations harnessed by neural networks and Transformers. Building on recent progress toward comprehending how networks execute distinct target functions, our study embarks on an exploration of t…

Cited by 0SourceScholar
2025

Fundamental Limits of Visual Autoregressive Transformers: Universal Approximation Abilities

ICML 2025poster

We investigate the fundamental limits of transformer-based foundation models, extending our analysis to include Visual Autoregressive (VAR) transformers. VAR represents a big step toward generating images using a novel, scalable, coarse-to-fine ``next-scale prediction'' framework. These models set a…

Cited by 0SourcePDFScholar
2025

Kernel Regression in Structured Non-IID Settings: Theory and Implications for Denoising Score Learning

NeurIPS 2025poster

Kernel ridge regression (KRR) is a foundational tool in machine learning, with recent work emphasizing its connections to neural networks. However, existing theory primarily addresses the i.i.d. setting, while real-world data often exhibits structured dependencies - particularly in applications like…

Cited by 0SourceScholar
2025

Looped ReLU MLPs May Be All You Need as Practical Programmable Computers

AISTATS 2025poster

Previous work has demonstrated that attention mechanisms are Turing complete. More recently, it has been shown that a looped 9-layer Transformer can function as a universal programmable computer. In contrast, the multi-layer perceptrons with $\mathsf{ReLU}$ activation ($\mathsf{ReLU}$-$\mathsf{MLP}$…

Cited by 0SourceScholar
2025

NRFlow: Towards Noise-Robust Generative Modeling via High-Order Mechanism

UAI 2025

Flow-based generative models have shown promise in various machine learning applications, but they often face challenges in handling noise and ensuring robustness in trajectory estimation. In this work, we propose NRFlow, a novel extension to flow-based generative modeling that incorporates second-o

Cited by 0SourcePDFScholar
2025

Unraveling the Smoothness Properties of Diffusion Models: A Gaussian Mixture Perspective

ICCV 2025poster

Diffusion models have made rapid progress in generating high-quality samples across various domains. However, a theoretical understanding of the Lipschitz continuity and second momentum properties of the diffusion process is still lacking. In this paper, we bridge this gap by providing a detailed ex…

Cited by 0SourcePDFScholar
2025

When Can We Solve the Weighted Low Rank Approximation Problem in Truly Subquadratic Time?

AISTATS 2025poster

The weighted low-rank approximation problem is a fundamental numerical linear algebra problem and has many applications in machine learning. Given a $n \times n$ weight matrix $W$ and a $n \times n$ matrix $A$, the goal is to find two low-rank matrices $U, V \in \mathbb{R}^{n \times k}$ such that th…

Cited by 0SourceScholar
2024

Is A Picture Worth A Thousand Words? Delving Into Spatial Reasoning for Vision Language Models

NeurIPS 2024poster

Large language models (LLMs) and vision-language models (VLMs) have demonstrated remarkable performance across a wide range of tasks and domains. Despite this promise, spatial understanding and reasoning—a fundamental component of human cognition—remains under-explored. We propose SpatialEval, a nov…

2024

Towards Few-Shot Adaptation of Foundation Models via Multitask Finetuning

ICLR 2024poster

Foundation models have emerged as a powerful tool for many AI problems. Despite the tremendous success of foundation models, effective adaptation to new tasks, particularly those with limited labels, remains an open question and lacks theoretical understanding. An emerging solution with recent su…

2024

Why Larger Language Models Do In-context Learning Differently?

ICML 2024poster

Large language models (LLM) have emerged as a powerful tool for AI, with the key ability of in-context learning (ICL), where they can perform well on unseen tasks based on a brief series of task examples without necessitating any adjustments to the model parameters. One recent interesting mysterious…

Cited by 348SourcePDFScholar
2023

A Graph-Theoretic Framework for Understanding Open-World Semi-Supervised Learning

NeurIPS 2023spotlight

Open-world semi-supervised learning aims at inferring both known and novel classes in unlabeled data, by harnessing prior knowledge from a labeled set with known classes. Despite its importance, there is a lack of theoretical foundations for this problem. This paper bridges the gap by formalizing a…

2023

The Trade-off between Universality and Label Efficiency of Representations from Contrastive Learning

ICLR 2023top-25%

Pre-training representations (a.k.a. foundation models) has recently become a prevalent learning paradigm, where one first pre-trains a representation using large-scale unlabeled data, and then learns simple predictors on top of the representation using small labeled data from the downstream tasks.…

2023

When and How Does Known Class Help Discover Unknown Ones? Provable Understanding Through Spectral Analysis

ICML 2023poster

Novel Class Discovery (NCD) aims at inferring novel classes in an unlabeled set by leveraging prior knowledge from a labeled set with known classes. Despite its importance, there is a lack of theoretical foundations for NCD. This paper bridges the gap by providing an analytical framework to formaliz…

2022

A Theoretical Analysis on Feature Learning in Neural Networks: Emergence from Inputs and Advantage over Fixed Features

ICLR 2022poster

An important characteristic of neural networks is their ability to learn representations of the input data with effective features for prediction, which is believed to be a key factor to their superior empirical performance. To better understand the source and benefit of feature learning in neural n…

Cited by 72SourcePDFScholar