Transformer Encoder Satisfiability: Complexity and Impact on Formal Reasoning

Fuente: arXiv
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Main Authors: Sälzer, Marco, Alsmann, Eric, Lange, Martin
Format: Preprint
Published: 2024
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author Sälzer, Marco
Alsmann, Eric
Lange, Martin
author_facet Sälzer, Marco
Alsmann, Eric
Lange, Martin
contents We analyse the complexity of the satisfiability problem, or similarly feasibility problem, (trSAT) for transformer encoders (TE), which naturally occurs in formal verification or interpretation, collectively referred to as formal reasoning. We find that trSAT is undecidable when considering TE as they are commonly studied in the expressiveness community. Furthermore, we identify practical scenarios where trSAT is decidable and establish corresponding complexity bounds. Beyond trivial cases, we find that quantized TE, those restricted by fixed-width arithmetic, lead to the decidability of trSAT due to their limited attention capabilities. However, the problem remains difficult, as we establish scenarios where trSAT is NEXPTIME-hard and others where it is solvable in NEXPTIME for quantized TE. To complement our complexity results, we place our findings and their implications in the broader context of formal reasoning.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18548
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transformer Encoder Satisfiability: Complexity and Impact on Formal Reasoning
Sälzer, Marco
Alsmann, Eric
Lange, Martin
Logic in Computer Science
Artificial Intelligence
Computational Complexity
Machine Learning
We analyse the complexity of the satisfiability problem, or similarly feasibility problem, (trSAT) for transformer encoders (TE), which naturally occurs in formal verification or interpretation, collectively referred to as formal reasoning. We find that trSAT is undecidable when considering TE as they are commonly studied in the expressiveness community. Furthermore, we identify practical scenarios where trSAT is decidable and establish corresponding complexity bounds. Beyond trivial cases, we find that quantized TE, those restricted by fixed-width arithmetic, lead to the decidability of trSAT due to their limited attention capabilities. However, the problem remains difficult, as we establish scenarios where trSAT is NEXPTIME-hard and others where it is solvable in NEXPTIME for quantized TE. To complement our complexity results, we place our findings and their implications in the broader context of formal reasoning.
title Transformer Encoder Satisfiability: Complexity and Impact on Formal Reasoning
topic Logic in Computer Science
Artificial Intelligence
Computational Complexity
Machine Learning
url https://arxiv.org/abs/2405.18548