Despite their success, large language models (LLMs) suffer from notorious hallucination issue. By introducing external knowledge stored in knowledge graphs (KGs), existing methods use paths as the medium to represent the graph information that send into LLMs. However, paths only contain limited graph structure information and are unorganized with redundant sequentially appeared keywords, which are difficult for LLMs to digest. We aim to find a suitable medium that captures the essence of structure knowledge in KGs. Inspired by the Neural Message Passing in Graph Neural Networks, we propose Language Message Passing (LMP) that first learns a concise facts graph by iteratively aggregates neighbor entities and transforms them into semantic facts, and then we performs Topological Readout that encodes the graph structure information into multi-level lists of texts to augment LLMs. Our method serves as a brand-new innovative framework that brings a new perspective into KG-enhanced LLMs, and also offers human-level semantic explainability with significant performance improvements over existing methods on all 5 knowledge graph question answering datasets. Code is available at https://github.com/wanjunhong0/LMP.

Supervised fine-tuning (SFT) is a crucial step for large language models (LLMs), enabling them to align with human instructions and enhance their capabilities in downstream tasks. Substantially increasing instruction data is a direct solution to align the model with a broader range of downstream tasks or notably improve its performance on a specific task. However, we find that large-scale increases in instruction data can damage the world knowledge previously stored in LLMs. To address this challenge, we propose LoRAMoE, a novelty framework that introduces several low-rank adapters (LoRA) and integrates them by using a router network, like a plugin version of Mixture of Experts (MoE). It freezes the backbone model and forces a portion of LoRAs to focus on leveraging world knowledge to solve downstream tasks, to alleviate world knowledge forgetting. Experimental results show that, as the instruction data increases, LoRAMoE can significantly improve the ability to process downstream tasks, while maintaining the world knowledge stored in the LLM. Our code is available at https://github.com/Ablustrund/LoRAMoE.