Contract¶
Core Idea¶
A contract is an explicit, multi-party specification of obligations, permissions, and consequences that binds the parties under an enforcement regime they have accepted as authoritative. Its structural content is not the promise itself but the bundling of four things behind a single agreement that all parties have committed to in advance: what each party must, may, and may not do; what each party is owed; what counts as a breach; and what enforcement follows from breach. The defining move is the gathering of these elements into one artifact whose authority every party has accepted, so that the diffuse web of mutual expectation is replaced by a single binding reference. A contract is therefore distinguished from a mere promise by the presence of a breach criterion and a remedy attached to an enforcement regime — without an authority able and willing to adjudicate and apply consequences, the document is an expression of intent rather than a contract.
The structural variables — parties with the capacity to bind themselves, an obligation set, performance conditions distinguishing fulfilled from breached, a remedy structure, an enforcement regime, a completeness trade-off, and an acceptance record — are abstract enough to recur across substrates, but the pattern is deeply framed by its legal and institutional origin and carries a normative obligation structure with it wherever it goes. The notion of obligation, the evaluative weight of "breach," and the appeal to an authoritative enforcer are not incidental decorations but load-bearing parts of the concept, and they keep it anchored in the human-practice cluster even as it extends to software interfaces (where the runtime or compiler is the enforcement regime) and to algorithmic settings (where executable code on a shared ledger is the enforcement substrate). The contract is, in this sense, a genuinely cross-substrate pattern that nonetheless imports its institutional frame rather than shedding it.
How would you explain it like I'm…
Promise With A Referee
The Deal With Consequences
Binding Agreement With Enforcement
Structural Signature¶
the parties able to bind themselves — the bundled obligation/permission set — the performance condition separating fulfilled from breached — the remedy structure — the accepted enforcement regime — the completeness trade-off over unforeseen contingencies
A configuration is a contract when each of the following holds:
- Binding-capable parties. Two or more parties have the standing to commit themselves, and an acceptance record establishes that each has assented to the agreement's authority in advance.
- A bundled obligation set. What each party must, may, and may not do — and what each is owed — is gathered into a single artifact, replacing a diffuse web of pairwise expectation with one binding reference.
- A breach criterion. A performance condition objectively separates fulfilled from breached for each obligation; an obligation whose fulfillment cannot be determined is structurally inert.
- A remedy structure. Defined consequences attach to breach — damages, liquidated damages, specific performance, exclusion — and the deterrence value sits here, not in the obligation language alone.
- An accepted enforcement regime. An authority able and willing to adjudicate breach and apply remedies is treated as authoritative; a clause means only what this regime can adjudicate, and without it the artifact is intent, not a contract.
- A completeness trade-off. No agreement foresees every contingency; specifying more costs effort up front and reduces downstream dispute, and where to set that boundary is an explicit design choice.
These compose into a binding governance artifact: parties accept an enforcement regime, bundle detectable obligations and their remedies into one reference, and deliberately set how much of an uncertain future to specify versus defer — the skeleton carrying its normative obligation frame wherever it travels.
What It Is Not¶
- Not an
interface. An interface specifies the shape of an interaction across a boundary — what calls are legal and what they return; a contract adds normative obligation, a breach criterion, a remedy, and an accepted enforcement regime. An interface that no authority enforces and whose violation carries no remedy is a contract's structural skeleton without its binding force (seeinterface). - Not a bare
credible_commitment. Credible commitment is one party making its own future course believable by removing its own options; a contract is a multi-party bundle of mutual obligations enforced by an external regime. The contract uses commitment, but adds counterparties, breach detection, and third-party adjudication. - Not
incentive_compatibility. Incentive compatibility designs a mechanism so that truthful or cooperative behavior is each party's self-interested choice; a contract instead imposes obligations backed by external remedy, working even when compliance is against immediate self-interest. One aligns incentives; the other compels regardless of them. - Not
mechanism_design. Mechanism design engineers the rules of a game so that desired outcomes emerge from strategic play; a contract is a specific governance artifact bundling obligations and enforcement. A contract may be an output of mechanism design, but it is not the design discipline itself. - Not
informal_enforcement. Informal enforcement relies on reputation, reciprocity, and social sanction with no formal adjudicator; a contract names an accepted enforcement regime able to adjudicate breach and apply remedy. The defining line is the presence of an authoritative enforcer, not merely social pressure. - Common misclassification. Calling any agreement or promise a "contract." The catch: ask whether there is a breach criterion and a remedy attached to an accepted enforcement regime; without an authority able and willing to adjudicate and apply consequences, the document is an expression of intent, not a contract.
Broad Use¶
- Law and economics. Sales, employment, marriage, lease, partnership, and treaty instruments are contracts in the strict sense, specifying performance, consideration, and remedy, and invoking a judicial enforcement regime.
- Software interfaces. API contracts, design-by-contract programming, and protocol specifications name the obligations of caller and callee, the legal request shapes, and the failure modes, with the runtime or compiler as the enforcement regime.
- Diplomacy and inter-state relations. Treaties specify obligations among states with enforcement via mutual sanction, international courts, or self-help, and the incomplete-contracting frame from economics maps directly onto them.
- Organizational governance. Service-level agreements, charters, and governance documents bind units within an organization, with an HR or audit function as the enforcement regime.
- Algorithmic and ledger settings. Smart contracts encode the obligation-and-consequence structure as executable code, with a blockchain as the enforcement substrate.
Clarity¶
The contract frame forces the unstated to become stated: what each party must do, what counts as having done it, and what happens if it is not done. It exposes the gaps in informal arrangements — the "you handle that, right?" left hanging — and converts them into specifiable obligations whose breach is detectable. The clarifying force is to replace a graph of pairwise, partly-tacit expectations with a single explicit artifact that any party, and any future arbiter, can consult, so that the question "what were we supposed to do?" has a determinate answer rather than a reconstruction. Two further clarifications follow from the structure. First, the frame makes the enforcement regime explicit as a separate question from the obligations: a clause means, in operational terms, only what the enforcement regime can adjudicate, so clauses outside the regime's reach are aspirational regardless of how firmly they are worded, and naming the regime first prevents the error of drafting obligations no one can enforce. Second, the frame makes detectability of breach a first-class requirement: an obligation that cannot be objectively determined as fulfilled or breached is structurally inert, and surfacing that requirement turns vague commitments into ones whose performance can actually be checked.
Manages Complexity¶
In multi-party interaction the alternative to a contract is a graph of pairwise expectations whose joint coherence must be reconstructed each time anyone acts — every participant carrying a private model of what every other owes them, with no shared reference to resolve disputes. A contract collapses that graph into a single artifact that every party and any future arbiter can consult, so that disputes narrow to interpretation of the artifact rather than reconstruction of intent. This is a substantial complexity saving: the cost of coordinating \(n\) parties drops from maintaining their pairwise expectations to maintaining one shared specification, and the same compression operation underlies why API specifications, treaties, and bylaws all take the form they take. The frame also manages the complexity of anticipation through the completeness trade-off. No contract foresees every contingency, and the structure makes the trade-off explicit: specifying more contingencies costs effort up front but reduces downstream interpretive dispute, while leaving more to interpretation costs less up front but more later, and the designer's job is to identify which contingencies are expensive enough to be worth specifying and which are cheap enough to defer to arbitration. Managing that boundary deliberately — rather than either over-specifying everything or leaving everything to good faith — is the contract's distinctive way of bounding the complexity of an uncertain future.
Abstract Reasoning¶
The structural variables of a contract are substrate-independent enough to support two reasoning moves that transfer across domains. Completeness-versus-incompleteness reasoning: because no contract anticipates every contingency, the trade-off between specifying more (cost up front) and leaving more to interpretation (cost downstream) is universal, and the analyst can reason about where to set that boundary by asking which contingencies are both likely and cheaply specifiable. Enforcement-attaches-to-specification reasoning: a clause means what the enforcement regime can adjudicate, so the reach of the regime bounds the operative content of the document, and clauses beyond that reach are aspirational — a structural fact that holds whether the regime is a court, a runtime, an audit committee, or a ledger. Two further structural moves follow from the variables. Detectability reasoning: an obligation whose fulfillment cannot be objectively determined is inert, so the design question "can breach of this be detected?" is prior to the question of how the obligation is worded. Remedy-design reasoning: the deterrence value of a contract sits in its remedy structure — damages, liquidated damages, specific performance, exclusion — rather than in the obligation language alone, so engineering the consequence of breach is often more powerful than tightening the description of the duty. Each move is stated in terms of obligations, enforcement, and remedy rather than any particular legal system, which is what lets the same reasoning serve a treaty negotiator, an API designer, and an employment lawyer — while the normative weight of "obligation" and "breach" travels with it.
Knowledge Transfer¶
The transferable content of the contract prime is a set of design interventions that recur across substrates because each attaches to the abstract obligation-breach-remedy-enforcement bundle, with the standing caveat that the bundle is heavily institutional in origin and carries its normative frame into every domain it enters. The first transferable move is name the enforcement regime first: if there is no body able and willing to adjudicate breach, the document is not a contract but an expression of intent and should be designed as such, and this diagnostic applies equally to a treaty without a binding court, an API "contract" without a runtime that enforces it, and a personal agreement with no third party to appeal to. The second is make breach detectable: an obligation that cannot be objectively determined as fulfilled or breached is structurally inert, so the same discipline that makes a service-level agreement specify a measurable uptime threshold makes a software contract specify a checkable precondition and a treaty specify a verification mechanism. The third is decide what to leave incomplete: identifying which contingencies are expensive enough to specify and which are cheap enough to defer to arbitration is the same trade-off in employment, protocol design, and treaty drafting, and making it consciously is the contract's distinctive contribution. The fourth is engineer the remedy, not just the obligation: because deterrence sits in the remedy structure, designing damages, liquidated-damages, specific-performance, or exclusion provisions well is more powerful than tightening the obligation language, and the same insight applies to a software contract's failure mode (panic, compile-time rejection) and a treaty's exit and sanction clauses. A software vendor and a hospital signing a service-level agreement — specifying uptime, incident response times, audit rights, data-handling obligations, liquidated damages for missed uptime, and a force-majeure clause — are instantiating exactly the same five-slot structure (parties, obligations, breach criteria, remedies, enforcement regime) that two states instantiate in an emissions treaty with verification and exit provisions, and that a function signature with contract assertions instantiates when the caller must supply a precondition, the callee guarantees a postcondition, and breach causes a panic or a compile-time rejection. The substrates differ; the structural bundle, and the normative obligation frame it carries, do not.
Examples¶
Formal/abstract¶
Design-by-contract programming instantiates the contract bundle in its most rigorous, checkable form — a genuine domain for the prime rather than a metaphor, because the runtime or compiler is a literal enforcement regime. Consider a function withdraw(account, amount) specified by contract. The binding-capable parties are the caller and the callee (the function), and the acceptance record is the type signature plus contract annotations that both compile against. The bundled obligation set is split into a precondition the caller must satisfy (amount > 0 && amount <= account.balance) and a postcondition the callee guarantees (account.balance == old(account.balance) - amount), together with an invariant (account.balance >= 0) that must hold across the call. The breach criterion is sharp and detectable: each clause is a Boolean predicate the runtime can evaluate exactly, so "fulfilled versus breached" is objectively decided, not reconstructed. The remedy structure is the consequence attached to breach — a precondition violation throws (or fails to compile under static contract checking), assigning blame to the caller, while a postcondition violation blames the callee. The completeness trade-off appears as the perennial question of how much of the input space to constrain in the precondition versus handle defensively in the body. Crucially, the enforcement-attaches-to-specification rule bites: a contract clause means only what the runtime can actually check, so an un-checkable comment ("amount should be reasonable") is aspirational, not operative — exactly the legal distinction between an enforceable term and mere intent.
Mapped back: A design-by-contract function signature instantiates the full five-slot bundle — binding parties, detectable obligations split into pre/postconditions, a blame-assigning remedy on breach, and a runtime enforcement regime — with the completeness trade-off in how tightly the precondition is drawn.
Applied/industry¶
A hospital and a software vendor signing a service-level agreement instantiate the same structure in its native legal substrate. The binding-capable parties are the two organizations; the acceptance record is the executed signature page. The bundled obligation set gathers what each must do: the vendor guarantees 99.9% monthly uptime, sub-four-hour incident response, and specified data-handling; the hospital grants audit rights and timely payment. The breach criterion is engineered to be detectable — uptime is measured against a defined monitoring methodology so "breach" is a computed threshold, not a judgment call, embodying the discipline that an obligation whose fulfillment cannot be objectively determined is structurally inert. The remedy structure carries the deterrence: liquidated damages of a fixed service-credit per hour of downtime below threshold, which the parties engineer deliberately because the deterrence sits in the consequence, not the obligation wording. The accepted enforcement regime is the courts (with an arbitration clause), and clauses beyond its reach would be aspirational. The completeness trade-off is explicit in a force-majeure clause that deliberately leaves pandemic-scale disruption to later interpretation rather than enumerating every contingency. The identical five-slot structure appears in a diplomatic substrate: an emissions treaty between two states bundles reduction obligations, makes breach detectable through a verification-and-monitoring mechanism, attaches remedy through sanction and exit provisions, and names enforcement via an international body or self-help — the incomplete-contracting frame from economics mapping directly onto the treaty's deferred contingencies.
Mapped back: A hospital-vendor SLA and an inter-state emissions treaty both bundle detectable obligations, engineer remedy where deterrence lives, name an accepted enforcement regime, and set a deliberate completeness boundary — instantiating the contract prime in commercial-legal and diplomatic substrates while carrying its normative obligation frame.
Structural Tensions¶
T1 — Specification on Paper versus Enforcement Reach (scopal). A clause means, operationally, only what the accepted enforcement regime can adjudicate; obligations beyond that reach are aspirational regardless of wording. The competing reality is the regime's actual capacity. The failure mode is drafting firm-sounding duties no authority can compel — a treaty term with no binding court, an API "contract" with no runtime check. Diagnostic: name the enforcement regime first and ask whether it can detect and remedy a breach of this clause; if not, the obligation is intent dressed as commitment, and relying on it is relying on good faith under a legal-looking surface.
T2 — Completeness versus Cost of Anticipation (temporal). No contract foresees every contingency; specifying more reduces downstream dispute but costs effort up front, and the future is genuinely uncertain. The failure mode runs both ways: over-specification that enumerates improbable cases (brittle, expensive, and still incomplete) or under-specification that defers too much to arbitration (cheap now, costly in disputes later). Diagnostic: ask which unforeseen contingencies are both likely and cheaply specifiable; a contract that tries to close every gap mistakes the completeness boundary for a failure to be eliminated rather than a trade-off to be set deliberately.
T3 — Detectable Breach versus Unobservable Performance (measurement). An obligation whose fulfillment cannot be objectively determined is structurally inert, yet much of what parties actually care about (good-faith effort, quality, intent) resists clean measurement. The failure mode is contracting on a proxy that is detectable but diverges from the real goal — specifying measurable uptime while the user cares about experienced reliability, inviting gaming of the metric. Diagnostic: ask whether the breach criterion measures the thing that matters or merely a checkable stand-in; if the parties optimize the proxy at the expense of the intent, the detectability requirement has displaced the obligation it was meant to secure.
T4 — Rigid Commitment versus Adaptive Renegotiation (sign/direction). The contract's value is binding force — fixing obligations so they cannot be unilaterally walked back — but rigidity is a liability when circumstances shift and the locked terms become inefficient or impossible. The failure mode is a contract so binding it compels performance that now harms both parties, or so loosely renegotiable that the commitment provides no security. Diagnostic: ask whether the agreement can adapt to changed conditions without dissolving its binding character; the competing prime is credible commitment, and a contract optimized purely for inflexibility forfeits the surplus that mutually-beneficial renegotiation would capture.
T5 — Bundled Single Reference versus Multi-Party Interpretation (coupling). The prime collapses a graph of pairwise expectations into one artifact every party consults, presupposing that the single reference is read identically by all. The failure mode is interpretation divergence: the same clause means different things to the parties, so the artifact that was supposed to eliminate dispute becomes its locus, and the bundling hides rather than resolves the disagreement. Diagnostic: ask whether the parties would, under stress, read each obligation the same way; if a clause admits materially different good-faith readings, the single-reference compression is illusory, and the contract has centralized an ambiguity rather than removing it.
T6 — Letter versus Spirit (frame). Contracts encode obligations as explicit, enforceable terms, but the relationship they govern carries a normative purpose the letter only approximates. The failure mode is literal compliance that defeats the agreement's intent — meeting every written term while subverting what the parties meant, or conversely a court rewriting clear terms in the name of "spirit" and destroying the predictability that made the contract worth signing. Diagnostic: ask whether honoring the literal obligations serves or frustrates the relationship's purpose; the normative frame the prime imports means breach can be technical-but-faithful or compliant-but-faithless, and treating the letter as the whole obligation misses the gap the enforcement regime must police.
Structural–Framed Character¶
Contract sits firmly at the framed end of the structural–framed spectrum, with a high aggregate near the framed pole. There is a genuine relational skeleton underneath — a multi-party bundle of obligations, a breach criterion, a remedy, and an enforcement regime — but four of the five diagnostics push it decisively toward framed, and only one reads partially structural.
The frame is heaviest on three diagnostics that score full marks. Institutional origin: the prime is born of contract law, and its constitutive notions — obligation, consideration, remedy, adjudication — are institutional artifacts, not formal-relational primitives. Human-practice-bound: a contract cannot exist without an accepted enforcement regime able and willing to adjudicate breach and apply consequences; the entry is explicit that without such an authority the document is "intent, not a contract," and even the software and ledger instances supply a runtime, compiler, or blockchain as the enforcer that stands in for a court. Import-versus-recognize: invoking the contract frame imports a whole normative apparatus — duties, blame-assignment, deterrence — rather than merely recognizing a pattern already wired into a physical system. The fourth full-mark diagnostic is evaluative weight: "breach" is inherently disapproving and "performance" approving; the concept carries its normative load wherever it travels, so it is not value-neutral until use is specified. Only vocab_travels reads a partial half: the obligation-breach-remedy-enforcement bundle does recur across treaties, APIs, and smart contracts, and a software contract can be told in the runtime's own terms, so the vocabulary is not wholly trapped in its legal home — but even there the design-by-contract case borrows "precondition," "blame," and "enforcement" straight from the legal frame. The relational skeleton is real, which is exactly why the prime is admitted at all; but the inherited institutional, normative, and practice-bound frame is so heavy and so load-bearing that the prime belongs near the framed pole, matching the assigned aggregate.
Substrate Independence¶
Contract is a moderately substrate-independent prime — composite 3 / 5 on the substrate-independence scale. The obligation-permission-breach-remedy-enforcement bundle is genuinely abstract — its structural variables (binding-capable parties, a bundled obligation set, a detectable breach criterion, a remedy structure, an accepted enforcement regime, a completeness trade-off) are spare enough to recur across substrates — and the recurrence is real: sales, employment, and treaty instruments in law; API contracts and design-by-contract programming where the runtime or compiler is the enforcement regime; service-level agreements and charters in organizational governance; and smart contracts where a blockchain is the enforcement substrate. What pins it firmly to the middle is that every instance imports the institutional frame rather than shedding it. The notion of obligation, the evaluative weight of "breach," and the appeal to an authoritative enforcer are load-bearing parts of the concept, not incidental decoration; a contract cannot exist without an accepted enforcement regime able and willing to adjudicate and apply consequences, so even the software and ledger instances must supply a runtime, compiler, or chain as the enforcer standing in for a court. There is no physical or biological substrate — the pattern lives entirely in the human-practice cluster, and the cross-domain transfer (smart contracts, API contracts) extends it but keeps the vocabulary inside that cluster. Genuine abstraction and demonstrated breadth lift it to a 3, but the deeply institutional, normative, practice-bound frame keeps all three components from climbing further.
- Composite substrate independence — 3 / 5
- Domain breadth — 3 / 5
- Structural abstraction — 3 / 5
- Transfer evidence — 3 / 5
Relationships to Other Primes¶
Parents (1) — more general patterns this builds on
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Contract presupposes Interface
The file: 'An interface that no authority enforces and whose violation carries no remedy is a contract's structural SKELETON without its binding force.' A contract = interface + normative obligation + breach criterion + remedy + accepted enforcement regime. It presupposes/enriches the interface. The 0.87 embedding-nearest is interface.
Children (1) — more specific cases that build on this
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Incomplete Contract is a kind of Contract
An incomplete contract is, structurally, a contract (a rule-set fixing outcomes for some contingencies) plus the distinctive move of an acknowledged gap + designated gap-handler + governance. contract is the canonical genus; incomplete_contract is the specific kind that deliberately leaves gaps. Phase-C already records the link to contract. The file severs it from interface (complete contract over its cases), delegation (only the decision-right piece), and optionality (a held right) — none is the genus; contract is. Good conviction: the is-a holds even though the prime is heavily framed (law/econ), because every instance is literally a contract or rule-set.
Path to root: Contract → Interface → Boundary
Neighborhood in Abstraction Space¶
Contract sits among the more crowded primes in the catalog (30th percentile for distinctiveness): several abstractions describe nearly the same structure, so a description that fits it will tend to fit its neighbors too — transporting it usually means disambiguating within this family rather than landing on it exactly.
Family — Adversarial Hardening & Rehearsal (5 primes)
Nearest neighbors
- Stage Gate Process — 0.73
- Constraint — 0.73
- Compellence — 0.73
- Credible Commitment — 0.72
- Decidability Computability — 0.72
Computed from structural-signature embeddings · 2026-06-14
Not to Be Confused With¶
The contract's nearest structural neighbor is the interface, and the two are genuinely close — both publish, on a boundary, what each side may expect of the other, and both let parties interact through a shared specification rather than by mutual inspection. The decisive difference is the normative obligation frame the contract carries and the interface does not. An interface specifies the shape of a legitimate interaction: which calls are well-formed, what arguments they take, what they return. It tells you how to interact correctly, but a violation is simply an error or an undefined behavior. A contract specifies duties — what each party is bound to do, what counts as failing to do it, and what remedy an accepted enforcement regime applies to that failure. The breach criterion and the enforcement-backed remedy are exactly what an interface lacks. The cleanest demonstration is design-by-contract programming, which sits at the overlap: a bare type signature is an interface, but the moment preconditions, postconditions, and a runtime that throws or refuses to compile on violation are added, an enforcement regime and a remedy appear, and the interface has become a contract. A practitioner who treats an interface as if it were a contract will assume duties and remedies that the mere shape-specification never established; one who treats a contract as a mere interface will draft obligations without asking who can detect and remedy their breach.
A second, more economic confusion is with incentive_compatibility. Both are ways of getting parties to behave as desired, but they work by opposite mechanisms. Incentive compatibility arranges the payoffs of a situation so that the behavior one wants is each party's own self-interested choice — no one needs to be compelled, because compliance is individually optimal given the structure. A contract instead imposes obligations backed by an external remedy, and it is built precisely for the cases where compliance is not in immediate self-interest: the remedy structure exists to make breach costly enough to deter a party who would otherwise prefer to defect. The two are complements as often as alternatives — a well-designed contract may also be made incentive-compatible so that enforcement rarely has to fire — but they are not the same object. Confusing them produces two errors: relying on a contract's coercive remedy where a self-enforcing incentive structure would have been cheaper and more robust, or relying on incentive alignment where the stakes demand an enforceable obligation with a remedy when alignment fails. The diagnostic is whether the desired behavior is self-interested (incentive compatibility's territory) or must be compelled against self-interest (the contract's).
The contract is also worth separating from informal_enforcement, with which it shares the function of holding parties to their word but differs in the nature of the enforcer. Informal enforcement operates through reputation, reciprocity, repeated dealing, and community sanction — there is no authoritative adjudicator, only the diffuse pressure of social and economic consequence. A contract names an accepted enforcement regime: a court, a runtime, an audit function, a ledger — some authority both able and willing to determine breach and apply a remedy. The Core Idea's insistence that without such an authority the artifact is "intent, not a contract" is precisely the line between the two. The distinction matters in practice because many real arrangements are governed by a mixture — a signed contract that the parties in fact enforce mostly through relationship and reputation, resorting to the formal regime only at the extremes — and mislabeling which mechanism is actually doing the work leads to over-investing in unenforceable formal terms, or to assuming a handshake carries a remedy it does not. Naming the enforcement regime first is the discipline that keeps formal and informal enforcement apart.
For a practitioner the cluster sorts by asking what supplies the binding force. An interface supplies a shape but no duty; incentive compatibility supplies aligned self-interest but no external remedy; informal enforcement supplies social pressure but no authoritative adjudicator; only the contract supplies the full bundle — detectable obligations, a remedy, and an accepted enforcement regime — and it imports a normative obligation frame that the structural neighbors do not. The recurring failure is to assume the contract's binding force is present when only one of its weaker neighbors actually is.
Solution Archetypes¶
No catalogued solution archetypes reference this prime yet.