GRM-002 Hard constraint layer: clause

Compound subject agreement

IF two or more singular subject heads are coordinated by AND, THEN use plural agreement ELSE evaluate the coordinator.

Why the rule exists

AND normally combines subject referents into a plural set.

Condition

The rule fires when this evaluates true. Paths marked below must be present in the fact base; the engine reports the rest rather than guessing them.

ALL
- clause.subject.coordinator eq "and"
- clause.subject.head_count gte 2
- clause.subject.denotes_single_unit eq false

Facts this rule reads

Fact paths read by GRM-002 and whether the analyser derives them
Path	Source
`clause.subject.coordinator`	You supply it
`clause.subject.head_count`	You supply it
`clause.subject.denotes_single_unit`	You supply it

Then

align — target clause.verb.number, value "plural"

Else

evaluate — target clause.subject.coordinator

LAKA

Smallest sufficient intervention

Yes

Primary axes

Sources

The Blue Book of Grammar and Punctuation — Jane Straus; Lester Kaufman
Accessible grammar, punctuation, examples, and exercises.
Practical English Usage — Michael Swan
Advanced grammar and usage reference for learners and teachers.
Grammar, Punctuation, and Sentence Structure — Purdue Online Writing Lab link
Practical mechanics, clause, sentence, punctuation, and style guidance.

The raw rule record

Verbatim from 07-core-grammar-rules.json. Also available at /v1/rules/GRM-002.

{
  "id": "GRM-002",
  "name": "Compound subject agreement",
  "domain": "grammar",
  "layer": "clause",
  "strength": "hard_constraint",
  "human_logic": "IF two or more singular subject heads are coordinated by AND, THEN use plural agreement ELSE evaluate the coordinator.",
  "when": {
    "all": [
      {
        "path": "clause.subject.coordinator",
        "operator": "eq",
        "value": "and"
      },
      {
        "path": "clause.subject.head_count",
        "operator": "gte",
        "value": 2
      },
      {
        "path": "clause.subject.denotes_single_unit",
        "operator": "eq",
        "value": false
      }
    ]
  },
  "then": [
    {
      "action": "align",
      "target": "clause.verb.number",
      "value": "plural"
    }
  ],
  "else": [
    {
      "action": "evaluate",
      "target": "clause.subject.coordinator",
      "rules": [
        "or_nor_proximity",
        "single_unit_exception"
      ]
    }
  ],
  "unless": [],
  "because": "AND normally combines subject referents into a plural set.",
  "diagnostics": [],
  "examples": {},
  "source_ids": [
    "BK-002",
    "BK-010",
    "WEB-011"
  ],
  "laka": {
    "smallest_sufficient_intervention": true,
    "primary_axes": [
      "scope",
      "depth",
      "magnitude",
      "reversibility"
    ]
  }
}