Fix oblique case noun agreement for Serbo-Croatian 5+ quantities

[nciric]

Summary

This change fixes noun agreement for 5+ quantities in Serbo-Croatian (sr, hr). In Serbo-Croatian, numerals 5+ (and indeclinable quantifiers like pet) always govern the Genitive Plural of the counted noun (5 brodova / 5 земаља), even when embedded in an oblique case context (e.g., Locative, Instrumental, Dative: "u 5 brodova", "sa 5 brodova").

• Overrides applyGatedGenitive in SerboCroatianCommonConceptFactory to enforce CASE_GENITIVE when mode == GOVERNED_PLURAL.
• Adds unit tests in QuantifyTest#testSerboCroatian to verify 5+ quantity handling under locative, instrumental, and dative contexts.

Before vs. After Code Fix Comparison

1. Masculine Noun Example: brod ("ship") with $n = 5$

Sentence Context & Case Parameter	WITHOUT Code Fix (main)	WITH Code Fix (PR #195)	Grammatical Evaluation
Nominative (Subject) {$unit :quantify withValue=5}	5 brodova / 5 бродова	5 brodova / 5 бродова	✅ Both correct
Locative (e.g. "o...") {$unit :quantify withValue=5 case=locative}	5 brodovima / 5 бродовима	5 brodova / 5 бродова	❌ Without: Ungrammatical ("o 5 brodovima") ✅ With: Correct ("o 5 brodova")
Instrumental (e.g. "sa...") {$unit :quantify withValue=5 case=instrumental}	5 brodovima / 5 бродовима	5 brodova / 5 бродова	❌ Without: Ungrammatical ("sa 5 brodovima") ✅ With: Correct ("sa 5 brodova")
Dative (e.g. "ka...") {$unit :quantify withValue=5 case=dative}	5 brodovima / 5 бродовима	5 brodova / 5 бродова	❌ Without: Ungrammatical ("ka 5 brodovima") ✅ With: Correct ("ka 5 brodova")

2. Feminine Noun Example: zemlja ("land/country") with $n = 5$

Sentence Context & Case Parameter	WITHOUT Code Fix (main)	WITH Code Fix (PR #195)	Grammatical Evaluation
Locative {$unit :quantify withValue=5 case=locative}	5 zemljama / 5 земљама	5 zemalja / 5 земаља	❌ Without: Ungrammatical ("u 5 zemljama") ✅ With: Correct ("u 5 zemalja")
Instrumental {$unit :quantify withValue=5 case=instrumental}	5 zemljama / 5 земљама	5 zemalja / 5 земаља	❌ Without: Ungrammatical ("sa 5 zemljama") ✅ With: Correct ("sa 5 zemalja")

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Detailed analysis

Serbo-Croatian Numerals 5+ and Oblique Case Governance

In Serbo-Croatian (Bosnian/Croatian/Montenegrin/Serbian or BCMS), the behavior of numerals 5 and above—along with indeclinable quantifiers like pet ("five"), šest ("six"), nekoliko ("several"), or mnogo ("many")—presents a classic linguistic phenomenon known as the Genitive of Quantification (genitivus quantitativus) combined with Case Masking / Case Invisibility.

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1. The Core Grammatical Rule

When cardinal numerals 5 and higher govern a noun phrase:

1. The numeral is indeclinable: It never inflects for case, gender, or number.
2. The governed noun phrase appears strictly in the Genitive Plural: Any modifying adjectives and the noun itself take the Genitive Plural endings (e.g., -a / -ova / -eva).
3. Obligatory case masking: Even when the overall Quantifier Phrase (QP) is embedded in an oblique case context (e.g., governed by a preposition requiring Locative, Instrumental, or Dative), external case assignment cannot override the internal Genitive Plural assignment.

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2. Examples Across Case Contexts

Consider the noun brod (m. "ship"):

• Singular Genitive: broda
• Plural Genitive: brodova
• Plural Locative / Dative / Instrumental: brodovima

A. Direct Case Contexts (Nominative / Accusative)

• Nominative (Subject):
  • Pet brodova je uplovilo u luku.
  • ("Five ships [Gen.Pl.] sailed into the port.")
• Accusative (Direct Object):
  • Vidim pet brodova.
  • ("I see five ships [Gen.Pl.].")

B. Oblique Prepositional Contexts (Locative, Instrumental, Dative)

Notice that the prepositional case requirement is "absorbed" or masked by the indeclinable numeral pet, preserving the Genitive Plural brodova:

• Locative context (Preposition o / na normally requires Locative Plural ending -ima):

  • Govorimo o pet brodova. (NOT: o pet brodovima)
  • ("We are speaking about five ships.")

• Instrumental context (Preposition sa normally requires Instrumental Plural ending -ima):

  • Stigao je sa pet brodova. (NOT: sa pet brodovima)
  • ("He arrived with five ships.")

• Dative context (Preposition ka / prema normally requires Dative Plural ending -ima):

  • Prilazimo ka pet brodova. (NOT: ka pet brodovima)
  • ("We are approaching towards five ships.")

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3. Comparison with Numerals 1–4

The behavior of 5+ contrasts sharply with smaller numerals:

Numeral	Morphosyntactic Category	Example Context	Case Behavior
1 (jedan)	Standard Adjective	sa jednim brodom	Fully inflects & agrees in gender, number, and case (Instrumental Sg).
2, 3, 4 (dva, tri, četiri)	Paucal Quantifiers	dva broda / sa dvama brodovima	Triggers Genitive Singular / Paucal in Nominative/Accusative. In formal register, can inflect for oblique cases (dvama, trima), though uninflected forms with Gen.Sg. (sa dva broda) are common in spoken speech.
5+ (pet, šest...)	Indeclinable Quantifiers	sa pet brodova	Fixed Genitive Plural across all syntactic positions and oblique case contexts.

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4. Diachronic & Theoretical Explanations

A. Historical Origin (Proto-Slavic)

Originally in Proto-Slavic, numerals 1–4 were adjectives, whereas 5–10 (pętь, šestь, etc.) were abstract feminine collective nouns (declining as $i$-stem singular nouns meaning "a group of five" or "a five-ness").

As nouns, they took partitive/adnominal complements in the Genitive Plural (e.g., "a five-ness of-ships"). Over time, as these words lost their nominal paradigm and became uninflected adverbial quantifiers, the Genitive Plural complement became frozen in place.

B. Syntactic Analysis (Generative Syntax / QP-Hypothesis)

In formal syntactic literature (e.g., Željko Bošković, Steven Franks):

1. Numerals 5+ head a Quantifier Phrase (QP): $[{\text{QP}} \text{pet} [{\text{NP}} \text{brodova}]]$
2. The functional head $Q^0$ (pet) assigns structural/inherent Genitive case to its inner complement (NP).
3. Because $Q^0$ is non-agreeing and opaque, when an external case assigner (like a preposition $P^0$) selects the QP, the external case feature cannot penetrate down to the complement NP, leaving the internal Genitive Plural case intact.

C. Verbal Agreement Default

Because the QP headed by 5+ lacks person/number/gender features, verbs agreeing with a 5+ subject take default agreement: 3rd Person Neuter Singular (or 3rd Person Singular in non-past tenses):

• Pet brodova je [3Sg] uplovilo [Neut.Sg]. ("Five ships have sailed in.")

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5. Academic References & Citations

1. Franks, Steven (1995). Parameters of Slavic Morphosyntax. Oxford University Press.
   • Chapter 3 ("Numeral Phrases") details the structural breakdown of QP vs. NP and explains case feature suppression/masking in Slavic numeral constructions.
2. Bošković, Željko (2006). "Case and Agreement with Genitive of Quantification in Slavic". Studia Linguistica, 60(1), 32–81.
   • Provides a detailed Minimalist account of how numerals 5+ in Serbo-Croatian/BCMS assign structural/inherent Genitive and why oblique cases cannot override it.
3. Browne, Wayles, and Alt, Theresa (2004). A Handbook of Bosnian, Serbian, and Croatian. SEELRC (Slavic and East European Language Resource Center).
   • Explains standard prescription, usage of pet + Genitive Plural in prepositional contexts, and lack of oblique declension.
4. Corbett, Greville G. (1983). Hierarchies, Targets and Controllers: Agreement Patterns in Slavic. Croom Helm.
   • Analyzes agreement mismatches and the syntactic behavior of quantified noun phrases across Slavic.
5. Alexander, Ronelle (2006). Bosnian, Croatian, Serbian, a Grammar: With Sociolinguistic Commentary. University of Wisconsin Press.
   • Provides descriptive paradigm charts and notes on numeral-noun agreement rules.

[nciric]

@grhoten still checking with Jelena about details (thou I think it's correct). Adding you to see if this is the correct way to tackle it.

[grhoten]

Changes seem reasonable, and there are tests.