arXiv Machine Learning

Stringological sequence prediction III: layered ziplines and a tradeoff between efficiency and expressivity

The paper introduces a new complexity measure, based on a restricted class of "layered zipline programs," which is weaker than the previously defined Arithmetic Repetition Complexity (ARC). This measure allows for a prediction algorithm that operates in quasilinear time and polylogarithmic space on highly-structured sequences, offering a more efficient solution at the cost of reduced expressivity compared to ARC. The work highlights a tradeoff between algorithmic efficiency and the breadth of sequences that can be effectively predicted.

arXiv Machine Learning
Sep 1

Where Induction Runs Out: Description-Length Difficulty and the Memorisation Gap in Integer-Sequence Benchmarks

The paper investigates integer‑sequence benchmarks from the OEIS by applying a two‑part minimum description length (MDL) learner that searches for P‑recursive recurrences. It finds that MDL difficulty correlates with a combinatorial parameter count, that most sequences fit a recurrence on a prefix but not at full length (the “wilderness” regime), and that language models do not hallucinate in the wilderness but instead hedge, showing that memorisation dominates perceived competence. The study provides a cheap, contamination‑free difficulty signal for OEIS‑derived benchmarks.

By Sabilashan Ganeshan
arXiv Machine Learning
Jul 28

Hallucination Rates in Language Generation

arXiv:2607. 23361v1 Announce Type: cross Abstract: Language generation in the limit is an elegant model introduced by Kleinberg and Mullainathan [KM24] to formally study language generation by an algorithm that learns solely based on example strings.

By Debmalya Panigrahi, Fan Wei, Ian Zhang
arXiv AI
Aug 7

The Impossibility Triangle of Long-Context Modeling

arXiv:2605. 05066v2 Announce Type: replace-cross Abstract: We identify and prove a fundamental trade-off governing long-sequence models: no model can simultaneously achieve (i) per-step computation independent of sequence length (Efficiency), (ii) state size independent of sequence length (Compactness), and (iii) the ability to recall a number of historical facts proportional to sequence length (Recall).

By Yan Zhou
arXiv Machine Learning
Sep 10

Length Generalization for Transformers via Compression

arXiv:2609.08851v1 Announce Type: new Abstract: Recent advancements in transformer length generalization theory enable us to reliably predict when a transformer can learn to solve a task. In particul...

By Georg Zetzsche, Hongjian Jiang, Andy Yang, Pascal Bergstr\"a{\ss}er, Marco S\"alzer, David Chiang, Anthony W. Lin
arXiv Computation and Language
Aug 28

ElementCheck: Complexity-Aware Long-Form Text Factuality Evaluation via Sentence Elements

ElementCheck is a new framework for evaluating the factuality of long-form text that addresses limitations of the traditional decompose‑retrieve‑verify pipeline. Rather than breaking sentences into atomic sub‑claims, it extracts entity pairs linked by verifiable connections to form an element graph, using the graph’s topology to gauge sentence complexity. This allows simple sentences to be verified directly while complex ones undergo targeted element‑level refinement, and the authors introduce the FastFact‑Sent benchmark to support fine‑grained evaluation, demonstrating consistent improvements across multiple backbone models.

By Xinming Wang, Haoran Du, Yi Chen, Jian Xu, Hongming Yang, Han Hu, Yulong Chen, Cheng-Lin Liu, Xu-Yao Zhang