feat(proofs): close lemma_build_yields_symmetric + vmodel_chain_two_steps#228
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feat(proofs): close lemma_build_yields_symmetric + vmodel_chain_two_steps#228
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…teps
Verus side: replace the assume(...) bridge in lemma_build_yields_symmetric
with explicit `assert forall|...| ... implies ... by { ... }` blocks for
both directions of backlink_symmetric. To make the spec-fn-side and the
requires-side share a common SMT trigger pattern, the corresponding
inner term accesses on backlink_symmetric (g.forward[src][i],
g.backward[tgt][j], etc.) now carry matching `#[trigger]` annotations.
The explicit skolemization in the assert-forall is what actually drives
the instantiation; the trigger pin guarantees the SMT pattern matches.
Rocq side: vmodel_chain_two_steps was Admitted with a note that the
prior statement was under-constrained — the proof needed to identify
the anonymous link target t1 from a1's r1-link with the named parameter
a2, and there was no premise forcing that. We pick option (2) from the
prior note: existentially quantify the intermediate. The resulting
theorem is what the V-model chain actually says ("a r1+r2 chain from
a1 lands at some downstream artifact") and admits a direct proof:
extract t1 from rule_satisfied/r1, use rule_target_kind r1 =
rule_source_kind r2 plus rule_satisfied/r2 to get t2, then close with
reach_direct + reach_trans.
Verifies: REQ-004
link_valid hands us [art_id t = link_target l], but reach_direct's has_link_to needs [link_target l = art_id t] (the obligation flips direction in the constructor's argument). Wrap the assumption in [symmetry]. Verifies: REQ-004
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⚠️ Performance Alert ⚠️
Possible performance regression was detected for benchmark 'Rivet Criterion Benchmarks'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.
| Benchmark suite | Current: 5494d54 | Previous: 92ad95d | Ratio |
|---|---|---|---|
query/10000 |
154678 ns/iter (± 626) |
109024 ns/iter (± 1298) |
1.42 |
This comment was automatically generated by workflow using github-action-benchmark.
📐 Rivet artifact deltaNo artifact changes in this PR. Code-only changes (renderer, CLI wiring, tests) don't touch the artifact graph. |
Codecov Report✅ All modified and coverable lines are covered by tests. 📢 Thoughts on this report? Let us know! |
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Summary
Closes the two remaining proof gaps in rivet's formal verification (REQ-004 follow-ups):
Gap 1 (Verus):
lemma_build_yields_symmetricassume(backlink_symmetric(g, s))bridge with explicitassert forall|...| ... implies ... by { ... }blocks for both directions ofbacklink_symmetric.#[trigger]annotations onbacklink_symmetric's inner term accesses so the spec-fn-side and the requires-side share a common SMT trigger pattern.assert forallis what actually drives the instantiation; the matching triggers guarantee the SMT pattern bridges.Gap 2 (Rocq):
vmodel_chain_two_stepsAdmittedwith a note observing the prior statement was under-constrained: there was no premise forcing the anonymous r1-link targett1to equal the named parametera2.a1lands at some downstream artifact."t1viaartifact_satisfies_rule s a1 r1, userule_target_kind r1 = rule_source_kind r2plusrule_satisfied s r2to push through tot2, then close withreach_direct+reach_trans. RealProof. ... Qed.CI status note
GitHub Actions has been backlogged at the time of this PR — Test, Verus, and Rocq jobs have all sat in
QUEUEDfor ~50+ minutes after PR creation with no runner pickup. The Verus and Rocq jobs are gated onneeds: [test], so they cannot start until the runner queue moves. The proofs were verified by careful manual inspection against the spec definitions:reachableconstructors and thelink_valid/artifact_satisfies_ruledefinitions;symmetrycorrectly bridges the direction mismatch betweenart_id t = link_target l(fromlink_valid) andlink_target l = art_id t(required byhas_link_to).assert forallskolemization produces the same instantiation pattern. If CI surfaces a residual SMT issue (most likely a missed trigger normalization), the next iteration will add explicit witness extraction inside theby { }blocks (e.g.,let j = choose|j: int| ...).Test plan
lemma_build_yields_symmetrichaving noassume(...)for the postconditionvmodel_chain_two_stepsending inQed.🤖 Generated with Claude Code