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feat(phd/igla): L-S40 MeshDeterminismCorrect — 2×2 GF16 mesh determinism under RR NoC#798

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feat(phd/igla): L-S40 MeshDeterminismCorrect — 2×2 GF16 mesh determinism under RR NoC#798
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Closes #797

Summary

Formal Coq proof (L-S40) that the 2×2 GF16 mesh is deterministic under round-robin NoC arbitration.

Given the same initial mesh state and the same input flit sequence, any two runs with global cycle offsets that are congruent modulo 4 produce identical outputs for all step counts. This establishes phase-offset independence of the arbitration result.

Anchor

  • φ² + φ⁻² = 3
  • Round-robin period = 4 (one slot per tile)
  • DOI: 10.5281/zenodo.19227877

Key results (zero Admitted)

Name Statement
rr_period_4 forall s ms, rr_step (s+4) ms = rr_step s ms
mesh_determinism forall init s1 s2 n, s1 mod 4 = s2 mod 4 -> rr_run init s1 n = rr_run init s2 n

Files changed

  • docs/phd/theorems/igla/MeshDeterminismCorrect.v — Coq source (193 loc, 0 Admitted, all Qed)
  • docs/phd/artifacts/coq_citation_map.json — new file mapping MeshDeterminismCorrect.mesh_determinismgf16_mesh_2x2_top.v arbiter

Verification

coqc 8.20.1 docs/phd/theorems/igla/MeshDeterminismCorrect.v  # exit 0

Foundation

This proof is the foundation for Wave-12 cross-die ledger receipt v2.


Apache-2.0 | Author: Dmitrii Vasilev admin@t27.ai

…ism under RR NoC

Closes #797

Formal proof that the 2×2 GF16 mesh is deterministic under
round-robin NoC arbitration.  Given the same initial mesh state,
any two runs with cycle offsets congruent mod 4 produce identical
outputs for all step counts.

Key results
- Lemma rr_period_4: rr_step (s+4) ms = rr_step s ms
- Theorem mesh_determinism:
    forall init s1 s2 n,
      s1 mod 4 = s2 mod 4 ->
      rr_run init s1 n = rr_run init s2 n
- Zero Admitted; all proofs end Qed
- coqc 8.20.1 exit 0

Anchor: φ²+φ⁻²=3  |  RR period 4  |  DOI 10.5281/zenodo.19227877
Foundation for Wave-12 cross-die ledger receipt v2

Also: create docs/phd/artifacts/coq_citation_map.json mapping
MeshDeterminismCorrect.mesh_determinism → gf16_mesh_2x2_top.v arbiter

Apache-2.0 | Author: Dmitrii Vasilev <admin@t27.ai>
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L-S40 Coq: MeshDeterminismCorrect proof tracking

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