arXiv AI

Introduction to Transformers: an NLP Perspective

arXiv:2311. 17633v2 Announce Type: replace-cross Abstract: Transformers have dominated empirical machine learning models of natural language processing.

arXiv AI
Sep 25

Your Transformer Can Hold Two Thoughts at Once: Evidence of Linear Superposition in LLMs

The paper demonstrates that Large Language Models, despite their non‑linear components, exhibit a fundamental linearity property: when inputs from two distinct text streams are linearly combined, the model outputs a superposition of the individual next‑token distributions. This "Superposition Linearity Hypothesis" appears to be an intrinsic feature of the Transformer architecture, tends to weaken during pretraining, but can be largely restored with lightweight fine‑tuning. The authors also present a guided decoding method that separates the superposed outputs, allowing two coherent continuations to be generated from a single forward pass.

By Pavel Tikhonov, Anton Korznikov, Matvey Mikhalchuk, Nikita Dragunov, Temurbek Rahmatullaev, Polina Druzhinina, Anton Razzhigaev, Ivan Oseledets, Elena Tutubalina
arXiv AI
Sep 3

A Survey of Transformer-based Language Models with Focus on Efficiency

The paper surveys Transformer-based large language models (LLMs) with a focus on efficiency, reviewing 312 articles that cover data curation, model design, downsizing, and dynamic inference. It also examines efficiency in adaptation strategies such as pre‑training, fine‑tuning, prompt‑engineering, and Retrieval‑Augmented Generation (RAG). A statistical analysis and evaluation of over 30 prominent NLP models on 13 benchmarks provide insights into both efficiency and efficacy, highlighting trends toward sustainable NLP practices.

By Wazib Ansar, Saptarsi Goswami, Amlan Chakrabarti
arXiv Computation and Language
Aug 31

Diverging Transformer Predictions for Human Sentence Processing: A Comprehensive Analysis of Agreement Attraction Effects

The study evaluates eleven autoregressive transformer models on English agreement attraction scenarios using a surprisal-based approach. Results show that while transformers match human reading times for prepositional phrase configurations, they perform poorly on object‑extracted relative clauses, with predictions diverging across models and failing to capture human interference patterns. The authors argue that current transformers cannot adequately model human morphosyntactic processing and call for more rigorous, comprehensive testing to avoid misleading conclusions from limited syntactic setups.

By Titus von der Malsburg, Sebastian Pad\'o
arXiv Machine Learning
Jun 17

An expressivity analysis of hierarchical modelling in deep transformers via bounded-depth grammars

arXiv:2606. 17522v1 Announce Type: cross Abstract: Deep neural networks are widely believed to derive their expressive power from their ability to form \textbf{hierarchical representations}, capturing progressively more abstract and compositional features across layers.

By Vinoth Nandakumar, Qiang Qu, Pramod Thebe, Sakshi Khachariya, Tongliang Liu