Reference

Standards & references

The mechanical contract invents one layer and borrows every other. This page lists the external standards it binds to, and the prior art it stands on - each link points at the source, not a summary.

§10 · Standards bindings

Nothing invented that already exists.

The entire novelty budget is spent on one layer: the judgment layer - executable contract terms with typed ports. Every other layer is an existing standard, consumed as-is. A supplier's Peppol stack already speaks every payload below.

Layer	Standard	Role
Invoice payload	EN 16931 / Peppol BIS Billing 3 ↗	invoice.submit port type; rules cite BT-terms (BT-146 price, BT-13 reference)
Order chain	Peppol post-award ↗	Order, Order Agreement, Despatch Advice - allocation.request / material.delivery ports
Payment status	ISO 20022 (pain.002 / camt) ↗	payment.confirm port
Transport	Peppol eDelivery (AS4) ↗	default profile, not a dependency - already carries signed non-repudiation of receipt
Application receipt	Peppol MLR ↗	our receipt rides the same pattern one level up: judged against the contract
Signatures	eIDAS (XAdES) / BankID / EUDI ↗	genesis signing, per-event signing, receipt seals
Timestamps	RFC 3161 ↗	receipt timestamping
Idempotency	IETF Idempotency-Key ↗	submission-id semantics, verbatim (the Stripe/PayPal pattern)
Legal form	Ricardian tuple ↗	{prose, parameters, spec} under one hash; prose governs on conflict

§11 · Prior art

The field, and the gap it leaves.

Forty years of standardizing every document around the contract - EDIFACT INVOIC in 1987, receipts at the transport level in the 90s, three generations of Swedish invoice formats - and the agreement itself was never once made machine-readable. Here is what comes closest, and what each one misses.

Contract as a boring deterministic machine

Flood & Goodenough, "Contract as Automaton" ↗

Gap Academic, one loan agreement, no ports/payloads/receipts, never productized

A contract a computer can evaluate compliance against

Surden, "Computable Contracts" ↗

Gap The concept and vocabulary, not a language or a system

Typed entry points with authorization

Daml choices on templates ↗

Gap No standards-native payloads, no procurement semantics, developer-facing

Minimal starved rule language, statically analyzable

Marlowe ↗

Gap Finance/blockchain habitat, no document ports