arXiv Machine Learning

When Can Prefixes Compile LoRA? Exact Resource-Capped Tests for Frozen Attention

arXiv AI
Aug 24

From Attention Masks to Inert Zero-Vector Tokens: OAttention and O-Closure for Token Dynamics

The paper introduces OAttention, a token‑level attention mechanism that assigns each token a presence coefficient based on its hidden representation. This coefficient both gates the token’s output and weights its contribution to other tokens, making zero‑vector tokens behave as true zeros and enabling exact null‑receiver, null‑source, and empty‑support properties. The authors extend this idea to local O‑components and an O‑Transformer, and demonstrate small performance changes when retrofitting a pretrained TabPFN model.

By Heyang Gong
arXiv Machine Learning
Sep 22

ValueDiff: Value-Geometric KV Cache Eviction for Sink-Suppressed LLMs

ValueDiff introduces a value‑geometric KV cache eviction strategy for large language models that suppress attention sinks. It ranks tokens by the L2 deviation of their value vectors from the cache mean, a score that aligns with minimal‑disturbance eviction under a max‑entropy assumption. Across several benchmarks—RULER, LongBench, and MATH‑500—ValueDiff consistently retains a higher proportion of useful tokens than prior methods, especially under tight cache budgets.

By Junyoung Park, Jungwook Choi, Mingu Lee
arXiv Machine Learning
Sep 18

A Table-Free Index for Tapered Memoization Grids: Compact Out-of-Core Evaluation of Functions of Sorted Arguments

The paper presents a table‑free index for tapered memoization grids, enabling compact out‑of‑core evaluation of functions that depend on sorted arguments. By showing that the grid’s key set corresponds to multiset combinations, the authors derive a closed‑form O(d) ranking and unranking scheme that removes the need for large preprocessing tables and allows order‑free parallel construction. The resulting values‑only flat array uses significantly less memory than hash‑map memoization, offers faster query times once cache limits are exceeded, and remains operable with memory‑mapped storage beyond RAM.

By Tamal Maharaj
arXiv AI
Sep 12

SemVerBench: Benchmarking LLM Comprehension of Version-Constraint Resolution Semantics

SemVerBench is a benchmark that evaluates how well large language models (LLMs) understand and apply version-constraint resolution semantics, such as determining whether a version satisfies constraints like ^1.2.3 or >=2.0. The study finds that many models struggle with certain corner cases, with GPT‑5.1 performing poorly while Claude and Opus perform much better. The authors suggest that the failures stem from an activation/application gap rather than a lack of knowledge, and recommend that coding agents delegate version resolution to a dedicated resolver tool.

By Qibai Chen, Zeming Liu