Dual-Density Inference for Efficient Language Model Reasoning
Zhengyi Zhao, Shubo Zhang, Yuxi Zhang, Huimin Wang, Binyang Li, Kam-Fai Wong
TL;DR
This paper identifies an efficiency gap in current LLM reasoning where internal computations rely on verbose natural language that hinders performance. It proposes Denser, a dual-density inference framework that uses high-density symbolic notation for intermediate reasoning and low-density natural language for final explanations, guided by a query-analysis module. Through extensive experiments across math, logic, coding, and general QA, Denser achieves substantial token reductions (up to 62%) while maintaining or improving accuracy and reducing latency, especially on multi-step problems. The approach is instantiated with domain-specific compression operators and density-aware prompting, and its effectiveness is demonstrated via ablations and case studies. Overall, the work shows that aligning representation density with the structural needs of reasoning tasks can yield tangible efficiency gains without sacrificing performance.
Abstract
Large Language Models (LLMs) have shown impressive capabilities in complex reasoning tasks. However, current approaches employ uniform language density for both intermediate reasoning and final answers, leading to computational inefficiency. Our observation found that reasoning process serves a computational function for the model itself, while answering serves a communicative function for human understanding. This distinction enables the use of compressed, symbol-rich language for intermediate computations while maintaining human-readable final explanations. To address this inefficiency, we present Denser: \underline{D}ual-d\underline{ens}ity inf\underline{er}ence, a novel framework that optimizes information density separately for reasoning and answering phases. Our framework implements this through three components: a query processing module that analyzes input problems, a high-density compressed reasoning mechanism for efficient intermediate computations, and an answer generation component that translates compressed reasoning into human-readable solutions. Experimental evaluation across multiple reasoning question answering benchmarks demonstrates that Denser reduces token consumption by up to 62\% compared to standard Chain-of-Thought methods while preserving or improving accuracy. These efficiency gains are particularly significant for complex multi-step reasoning problems where traditional methods generate extensive explanations.
