ABI Layer 4: prove the FFI result-code seam is injective + faithful#45
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Flagship semantic proof: an Alloy binary relation satisfies the `one` field multiplicity iff every live source maps to exactly one target (target-count = 1) — the OpenAPI "required, single-valued" property. Sound+complete Dec, certifier into the ABI Result codes proven sound, positive control + negative control (a one-source/two-target instance, the Alloy counterexample, is provably rejected). Verified with idris2 0.7.0 (build clean, zero warnings) + adversarial false-proof rejection. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Adds Alloyiser.ABI.Invariants over the existing Semantics model: proves the multiplicity-subsumption theorem oneImpliesLone (OneTargetFor s r -> LoneTargetFor s r) plus its field-level lift, a sound+complete Dec for LoneTargetFor, a sound ABI-Result certifier, and certifyOneEntailsLone tying the two verdicts. Controls: zero-target source is lone (positive), two-target source is not lone (negative), and lone does NOT entail one (strictness / non-vacuity). Distinct from and deeper than the Layer-2 `one` theorem. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Prove the alloyiser FFI result-code encoding is sound: distinct ABI outcomes never collide on the C wire and the integer faithfully round-trips back to the ABI value. - intToResult decoder (boolean Bits32 == so round-trip Refls reduce) - resultRoundTrip : intToResult (resultToInt r) = Just r - resultToIntInjective derived from the round-trip via justInj+cong - positive controls (decode 0/7/8) and a machine-checked non-vacuity control (resultToInt Ok /= resultToInt Error) Genuine proof only: no believe_me/postulate/assert_total/%hint. multToInt is export-only (non-reducing across modules) so it is out of scope here without widening Foreign's visibility. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>
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Summary
Layer 4 (seal the ABI↔FFI seam): proves the FFI result-code encoding (
resultToInt) is a sound, lossless wire encoding — decoderintToResultwithresultRoundTrip, from whichresultToIntInjectiveis derived. Distinct ABI outcomes never collide on the C wire. Complements the structuralabi-ffi-gate.py.New module
*.ABI.FfiSeam(importsTypes). Positive + non-vacuity controls. (Note:multToIntinForeignisexport-only so it doesn't reduce across modules — left to a future Foreign-visibility change rather than a proof cheat.)Testing
Idris2 0.7.0
--build→ exit 0, zero warnings. Adversarial rejection confirmed.build/removed. Nobelieve_me/postulate/sorry.🤖 Generated with Claude Code
https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Generated by Claude Code