Search-to-Decision Reductions for the Linear and General Code Equivalence Problems

Abhinaba Mazumder

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arXiv · 2608.10967

Search-to-Decision Reductions for the Linear and General Code Equivalence Problems

Abhinaba Mazumder

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Abstract

In this paper, we present efficient search-to-decision reductions for the Linear Code Equivalence (LCE) and Generalised Code Equivalence (GCE) problems. Our methodology is inspired by the recent search-to-decision reduction for Permutation Code Equivalence. We demonstrate how to recover the permutation component of the equivalence using a decision oracle, and subsequently show one way of recovering the diagonal and field automorphism components in deterministic polynomial time by leveraging the elegant Engel-Schneider algorithm for diagonal equivalence.

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Abhinaba Mazumder. 2026-08-11. Search-to-Decision Reductions for the Linear and General Code Equivalence Problems. https://arxiv.org/abs/2608.10967

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