Strict rules: boundaries

What the construct does NOT do in 0.2: limits, closed lists, neighbouring constructs, and the selection rule.

OverviewBoundariesCorpus formsPitfalls

Does not do

• Does not refuse. An unfired strict rule gives no Refuted: absence of inference is Not established, not refuted. Negative support comes only from explicit negations — a not p(x) head, a negative fact, closure.
• Is not defeated. Nobody removes strict support: neither defeater, nor priority, nor conditional priority. Two strict inferences with opposite heads are both preserved — Contradiction.
• Does not read contested premises. A fact in Contradiction does not establish a bare body literal: the rule stays silent where a naive reading expected firing. Deliberate work with a contested fact goes through supported(P) with justification.
• Does not infer from a court’s silence. A judgment-channel relation in the body yields REQUIRES_JUDGMENT at any rule strength: strict does not turn “the court decides” into “computed”.
• Does not bind variables by comparison. Comparison, negation, and not_known do not bind variables: the head must rest on a positive literal.

Reserved and closed

• Rule strength is mandatory: use strict, defeasible, or defeater; without it the parser rejects (LDC-E0201).
• scope, effective, defeat — at most one clause per block; a repeat — LDC-E1329. Several when clauses — a conjunction in written order; several then clauses — several head rules.
• Names event, case, calendar, action — hard keywords: the binder for event: … gives LDC-E0203.
• Underscore _ is legal only as an argument of a positive body literal (“there exists a value”); in a head, under not, in a status test, and in a case — LDC-E0207.

Neighbours and selection rule

• strict vs defeasible: exceptions possible in principle — defeasible; impossible by substance — strict. Changing the answer retroactively requires changing the strength (plus see the defeasible rules page).
• strict vs definition … exact: a named qualification of a concept — a definition (see the definitions page); a nameless inference from facts — a rule. Statuses match; the difference is in the proof graph (was_derived_from).
• strict with then not p(x) vs defeater: closed refusal (Refuted) vs removed support (Not established, not refuted). See the priority page.
• Strict conflict (Contradiction forever) vs resolvable conflict (defeasible + priority): decide before writing rules, not after the first Contradiction. See the priority page.