Pengfei Zhou

Author directory

Also published as: 鹏飞 周


2026

Large skill libraries are now standard equipment for LLM agents, and which subset reaches the prompt decides what the agent can do. Enumeration and top-K embedding retrieval both treat skills as independent documents, assuming relevance is a property of one skill at a time. It is not: skills depend on, conflict with, specialize, and duplicate one another, so the closest match to a task can name it while omitting a prerequisite it needs. Graph retrieval encodes these relations but spends them in a fixed pipeline, handing the agent an opaque bundle. We present SkillDAG, which exposes a typed skill graph to the LLM as an agent-callable interface rather than consuming it for the agent: search returns vector matches, typed-edge neighbors, and conflict signals, and a propose-then-commit protocol lets it register execution-backed edges as it works. Across two benchmarks and three model families, SkillDAG outperforms full-library prompting, vector retrieval, and Graph-of-Skills, gaining +14.3 points of ALFWorld success and tying only at ceiling; its ranking holds flat across a 10× pool expansion that degrades the fixed pipeline. Inter-skill structure, these results suggest, is worth more to an agent that can query and revise it than to a retriever that consumes it.
Multi-hop question answering requires retrieving and integrating multiple pieces of evidence distributed across documents. Recent graph-based methods improve multi-hop reasoning through graph traversal over relational evidence structures. However, existing methods rely on independent path ranking during evidence organization, which often produces redundant and reasoning-incomplete evidence sets due to substantial structural overlap among selected graph paths. In this work, we argue that graph-based evidence organization may, to some extent, be formulated as a constrained evidence subgraph optimization problem. Based on this perspective, we propose CROG, a coverage-aware reasoning optimization framework that performs marginal-gain-based path selection to favor previously uncovered reasoning steps while suppressing redundant evidence, with node-budget and connectivity constraints to encourage compact and coherent evidence subgraphs. Experiments on multiple benchmarks demonstrate that CROG achieves superior reasoning performance while using fewer evidence units on average, and analysis based on exhaustive optimal search further validates the effectiveness of the greedy optimization strategy.
True general intelligence requires not only a model of the physical world but also a social world model: the capacity to infer how individual mental states interact and crystallize into group-level outcomes. Despite notable progress in individual-level Theory of Mind (ToM) reasoning, existing multimodal large language models systematically fail at this: collective behavior emerges non-linearly from social tensions, conformity dynamics, and structural constraints, and cannot be recovered by summing individual intentions. We present GroupToM-Bench, the first multimodal benchmark for group-level ToM, built around a causal chain spanning micro-level BDI states (belief, desire, intention), meso-level group tension and structural constraints, and macro-level outcome prediction and mechanistic attribution. To probe this full arc, we develop a seven-level cognitive audit framework. Experiments reveal that frontier models perform significantly below human levels, exposing fundamental blind spots in modeling social structures and nonlinear collective behavior.

2025

Reasoning is an essential capacity for large language models (LLMs) to address complex tasks, whereas the identification of process errors is vital for improving this ability. Recently, process-level reward models (PRMs) were proposed to provide step-wise rewards that facilitate reinforcement learning and data production during training and guide LLMs toward correct steps during inference, thereby improving reasoning accuracy. However, existing benchmarks of PRMs are text-based and focus on error detection, neglecting other scenarios like reasoning search. To address this gap, we introduce MPBench, a comprehensive, multi-task, multimodal benchmark designed to systematically assess the effectiveness of PRMs in diverse scenarios. MPBench employs three evaluation paradigms, each targeting a specific role of PRMs in the reasoning process: (1) Step Correctness, which assesses the correctness of each intermediate reasoning step; (2) Answers Aggregation, which aggregates multiple solutions and selects the best one; and (3) Reasoning Process Search, which guides the search for optimal reasoning steps during inference. Through these paradigms, MPBench makes comprehensive evaluations and provides insights into the development of multimodal PRMs.

2023

“差比句是用来表达两个或多个事物之间的相似或不同之处的句子结构,常用句式为“X比Y+比较结果”。差比句存在多种结构变体且大量存在省略现象,造成汉语语法研究和自然语言处理任务困难,因此实现差比句结构的识别和对其缺省结构进行补全非常有意义。本文采用序列化标注方法构建了一个差比句语料库,提出了一个能够融合字与词信息的LatticeBERT-BILSTM-CRF模型来对差比句结构自动识别,并且能对缺省单位进行自动补全,实验结果验证了方法的有效性。”