Theorem · external algebraic reduction

FPRD-RDV-T01

Reversible reachability is equivariant ideal membership

Exact statement

For an orbit-finitely presented reversible system with transition binomials vi−uiv_i-u_i, source and target monomials s,ts,t satisfy s↔∗ts\leftrightarrow^* t exactly when t−st-s belongs to the ideal generated by all embedding-renamed vi−uiv_i-u_i. On a homogeneous data structure, the same finite renamings can be realized by automorphisms.

StatusPublished theorem; reduction reconstructed in the FPRD exposition
External reviewThe underlying theorem appeared at LICS 2024. No external review of the FPRD exposition is recorded.

Context

A rewrite step contributes a monomial context times a renamed transition difference; a path therefore telescopes to an ideal certificate.

Hypotheses and scope

  • Rules are symmetric.
  • Every rule and marking has finite support.
  • The source action is by embeddings; homogeneity is needed only when that action is replaced by automorphisms.

Proof or evidence

The forward direction is telescoping. The reverse direction is the binomial-ideal theorem for symmetric commutative rewriting, lifted equivariantly by the cited source.

Verification notes

The embedding action was restored in the theorem statement. An independent Buchberger implementation agreed with reversible reachability on 7,120 finite queries; the directed hostile control fails exactly as expected.

Limitations

  • Ideal membership becomes an algorithm only when a suitable basis can be computed.

Open work

Seek a specialist check of the automorphism-versus-embedding presentation used on the page.