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Linglib.Theories.Syntax.Minimalism.Core.CyclicAgree

Cyclic Agree @cite{bejar-rezac-2009} #

@cite{bejar-rezac-2009} derive person hierarchy (PH) effects from three independently motivated mechanisms:

  1. Articulated φ-features: person is decomposed into hierarchical segments — [π] ⊂ [participant] ⊂ [speaker]/[addressee] — each of which can independently enter Agree.
  2. Feature-relativized locality: a probe segment [uF] only sees goals bearing [F]; a goal lacking [F] is bypassed, leaving an active residue.
  3. Cyclic expansion: v's probe first Agrees with the IA (cycle I), then with the EA (cycle II). The IA is preferred because cyclicity puts it in the search space first.

The interaction of probe articulation and cyclic Agree derives:

Person Geometries #

Two attested geometries for the innermost feature:

Person Licensing and Repair #

The Person-Licensing Condition (PLC) requires every π-feature to be licensed by Agree. In inverse contexts, the EA's π-features are not licensed by the core probe, triggering repair strategies:

Both strategies are derivationally bounded: they occur in all and only inverse contexts.

Integration #

Connects to PersonGeometry.lean via bridge theorems. The direct/inverse classification predicts which languages show differential P indexing (Basque, Georgian fragments).

A single segment in an articulated person feature structure.

Segments are privative features organized in a containment hierarchy. Every person value bears [π]; SAPs additionally bear [participant]; the innermost feature ([speaker] or [addressee]) distinguishes 1st from 2nd person.

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      Which feature distinguishes 1st from 2nd person.

      • standard: [speaker] distinguishes 1st (Basque, Georgian)
      • addressee: [addressee] distinguishes 2nd (Nishnaabemwin, Mohawk)
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          @[reducible, inline]

          An articulated probe: a list of unvalued segments, ordered from outermost (most general) to innermost (most specific).

          Languages vary parametrically in probe articulation:

          • Flat [u-3]: no PH sensitivity (e.g., Swahili, Abkhaz)
          • Partial [u-3-2]: distinguishes SAP from 3P (e.g., Basque, Georgian)
          • Full [u-3-2-1]: distinguishes all persons (e.g., Nishnaabemwin, Mohawk)
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            Partial probe: [uπ, uParticipant]. Distinguishes SAP from 3P. Geometry-independent: [participant] is the same in both geometries.

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              A language's agreement system: the geometry and characteristic probe.

              @cite{bejar-rezac-2009} parameterize crosslinguistic variation by two choices: (1) which geometry organizes the innermost feature, and (2) how articulated the probe is. The full probe depends on the geometry (standard uses [speaker], addressee uses [addressee]).

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                    Basque/Georgian: partial probe, standard geometry.

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                      Active residue: unmatched probe segments after Agree with a goal DP.

                      Each probe segment that has a corresponding segment in the goal's person specification is deactivated (matched). Segments without a match remain active and can participate in further Agree on the next cycle.

                      This is the core operation of @cite{bejar-rezac-2009}: partial matching of articulated probes drives agreement displacement.

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                        Which argument controls the core agreement slot.

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                            Does the EA Agree with residue segments on cycle II?

                            Returns true iff the EA matches at least one segment that the IA left unmatched.

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                              Determine which argument controls the core agreement slot.

                              Cycle I: probe Agrees with IA. If residue remains, cycle II: probe Agrees with EA. EA controls iff it matches any residue segment; otherwise IA controls (either it fully checked the probe, or it left residue the EA couldn't match).

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                                The person value that the core agreement slot realizes.

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                                  Which cycle valued the probe's remaining segments.

                                  @cite{bejar-rezac-2009} §3.2: when the probe is valued on two different cycles, the morphological realization can differ. Georgian uses m- (first cycle) vs v- (second cycle) for 1sg agreement; Nishnaabemwin uses -in (1P, cycle II) vs -igw (3P, cycle II) vs -aa (default/cycle I only).

                                  Returns (cycleI, cycleII) — the segments deactivated on each cycle.

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                                    Was the probe valued on two distinct cycles?

                                    True when both the IA (cycle I) and EA (cycle II) matched at least one segment. This is the configuration that creates second-cycle morphological effects in languages like Georgian and Nishnaabemwin.

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                                      Inverse context: the core π-probe on v does NOT Agree with the EA.

                                      This occurs when either (a) the IA fully checks the probe, leaving no residue, or (b) residue exists but the EA cannot match any of it. Inverse contexts trigger PLC violations on the EA's π-features, requiring repair strategies (added probe or R-Case).

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                                        Direct context: the EA Agrees with at least one residue segment.

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                                          The Person-Licensing Condition (PLC).

                                          @cite{bejar-rezac-2009} eq. (13): "A π-feature [F] must be licensed by Agree of some segment in a feature structure of which [F] is a subset."

                                          In inverse contexts, the EA's π-features are not licensed by the core probe (because the probe either has no residue or residue the EA can't match). This drives repair strategies.

                                          Returns true if the EA is person-licensed (its π-features were checked by the core probe on cycle II).

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                                            PLC violation: EA is NOT person-licensed. Exactly characterizes inverse contexts — this is the paper's key insight connecting syntactic derivation to morphological repair.

                                            Repair strategies for PLC violations in inverse contexts.

                                            @cite{bejar-rezac-2009} §4 identifies two strategies:

                                            • addedProbe: an extra probe is inserted on v_II, creating an additional agreement slot for the EA (Nishnaabemwin, Mohawk, Basque)
                                            • rCase: the IA receives a special oblique Case distinct from the regular v-assigned Case (Kashmiri)
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                                                Does a given EA→IA combination require repair under this system?

                                                Repair is needed iff the context is inverse.

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                                                  In the standard geometry, a person value has [participant] as a segment iff DecomposedPerson.hasParticipant is true.

                                                  In the standard geometry, 3rd person has exactly one segment ([π]).

                                                  Flat probe: IA always fully checks the probe, regardless of person.

                                                  Flat probe: IA always controls — no PH effects.

                                                  Flat probe: all contexts are inverse (no EA agreement).

                                                  Partial probe: same behavior in both geometries, since [participant] is geometry-independent.

                                                  Basque: 3→3 = 3 (IA controls, inverse — residue [uParticipant] unmatched by either argument).

                                                  Nishnaabemwin: 3→3 = 3 (IA controls, inverse — residue [uParticipant, uAddressee] unmatched by 3P EA).

                                                  Nishnaabemwin: 3→1 is inverse despite residue, because EA (3P) can't match [addressee].

                                                  Georgian second-cycle effect: 1sg agreement is m- when valued on cycle I (IA=1, any EA), but v- when valued on cycle II (EA=1, IA=3).

                                                  Nishnaabemwin: 2→1 has a second-cycle effect (IA checks [π,participant], EA checks [addressee] on cycle II).

                                                  When EA and IA have the same person, IA always controls (the EA contributes nothing new — every segment it could match was already matched by the identical IA).

                                                  The proof proceeds by showing that activeResidue is idempotent when applied with the same goal: if some segments survive matching against personSpec(p), applying the same filter again removes nothing, so eaAgrees returns false.

                                                  The direct/inverse split exhaustively partitions the paradigm: every EA→IA combination is either direct or inverse, never both.

                                                  In a partial-probe language like Basque/Georgian, object (P) agreement is person-conditioned: the object controls agreement iff the context is direct (EA > IA on the person hierarchy). This predicts that SAP objects trigger agreement displacement to EA, while 3P objects don't.

                                                  Formally: for a fixed 3P EA (the "subject" in a canonical transitive), a SAP IA triggers direct context (EA controls → "no P indexing"), but this is backwards from the traditional description. Let's think about it from the P indexing perspective:

                                                  In Basque, the agreement slot tracks the controller. When IA is SAP, IA controls (inverse) — the agreement tracks IA, reflecting the object. When IA is 3P, EA controls (direct) — agreement tracks EA, not the object.

                                                  So pIsIndexed ↔ the IA controls (the agreement slot shows the object's features) ↔ inverse context.

                                                  Differential P indexing prediction: the SAP/3P split in object agreement (Basque pIsIndexed, Georgian pIsIndexed) is exactly the inverse/direct split of the partial probe.

                                                  An object (IA) is "indexed" when the core agreement slot tracks the IA's person features, which happens iff the context is inverse (IA controls). SAP IAs always produce inverse contexts; 3P IAs produce direct contexts (when EA is SAP).

                                                  This theorem proves the key direction: SAP IA → inverse (indexed).

                                                  Count inverse contexts in a 3×3 paradigm.

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                                                    Swahili (flat): all 9 cells are inverse (no PH sensitivity).

                                                    Basque (partial): 7 inverse, 2 direct (only SAP EA + 3P IA).

                                                    Nishnaabemwin (full): 6 inverse, 3 direct.