McPherson and Lamont (2026): Poko Postlexical Tone Requires Serial, Directional Evaluation #
This file formalizes the argument of [McPL26] that Poko postlexical tone
resists global constraint evaluation. No ranking or weighting of the paper's four
faithfulness constraints derives both nān + rī^H + nā 'I ate a pig' and kāk^H + rī^H
'his pig': the ranking argument is an inconsistent set of elementary ranking conditions
derived from the candidates' violation profiles (parallel_OT_inadequate), and the
weighting argument a contradiction in which one constraint's weight must both exceed and
fall below a sum of others (weighted_HG_inadequate). Directional Harmonic Serialism after
[Lam22d], with the constraint against floating tones evaluated left to right,
converges on every attested form, whereas right-to-left evaluation converges on the wrong
form and a count-based constraint yields a divergent tie ([Pru09]); the further
tableaux show the repair of falling contours, the blocking of crowding, and forced
tautomorphemic docking. Every step witness is decided.
Implementation notes #
The lexical data live in Fragments.Poko.Tone; the tableaux, rankings, and serial
derivations are the substrate's harmonic-serialism and tableau apparatus.
References #
Candidates (eqs. 57, 58) #
Winner/loser candidate pairs from [McPL26] eqs. 57 and 58.
- nanWinner : Cand
(57c) winner of
/nān + rī^H + nā/: rī's H docks rightward onto nā. - nanLoser : Cand
In the (57b) loser, the floating H deletes instead.
- kakWinner : Cand
(58c) winner of
/kāk^H + rī^H/: both floating Hs delete. - kakLoser : Cand
In the unattested MAX(H)-dominant winner (58b), one H docks and one deletes.
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- McPhersonLamont2026.instDecidableEqCand x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯
Constraints (eq. 7, eq. 59 columns) #
MAX(H) (eq. 7c): one violation per H tone deleted by GEN.
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DEP(link)/H (eq. 7a): one violation per inserted H-associated link.
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MAX(M) (eq. 7c analogue): one violation per M tone deleted.
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MAX(link)/M (eq. 7b analogue): one violation per deleted M-tone link.
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The eq. 59 columns; *FLOAT factored out per the paper's candidate restriction.
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Derived ERCs #
ERC of a winner/loser pair via ercOfProfiles ([Pri02]).
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- One or more equations did not get rendered due to their size.
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ERC for the /nān + rī^H + nā/ winner-loser pair.
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ERC for the /kāk^H + rī^H/ winner-loser pair.
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The ranking-paradox support.
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The ranking paradox (eq. 59) #
Parallel OT cannot model Poko (eq. 59): the derived support is ERC-inconsistent, since no ranking of the four constraints satisfies both of its ERCs.
Weighted HG inadequacy #
Weighted HG cannot model Poko, since MAX(H) must both exceed and undercut the other
three weights' sum (paper p. 32) and no ℚ-weighting satisfies both.
Shared fig. 2 ranking #
Non-float tail of the fig. 2 ranking, in (60) column order.
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The fig. 2 ranking (fig. 3 subset); only *FLOAT^→ is directional.
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Left-to-right directional HS over stdRanking — the paper's positive analysis.
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- McPhersonLamont2026.lrDerivation input = { gen := Autosegmental.Candidate.gen, ranking := McPhersonLamont2026.stdRanking }
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Fig. 3: LR vs RL over /kāk^H + rī^H + dō^H/ #
Fig. 3 input /kāk^H + rī^H + dō^H/: each M linked, each H floating.
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The faithful candidate of the input.
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Directional-LR derivation (*FLOAT^→).
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Mirror under *FLOAT^← (starFloatBlockRev) — the wrong-form counterexample.
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- McPhersonLamont2026.Fig3.derivationRL = { gen := Autosegmental.Candidate.gen, ranking := Tone.haveTone :: Tone.starFloatBlockRev ++ McPhersonLamont2026.rankingTail }
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The LR final form [kāk rī dō]: all floating Hs deleted (fig. 3 thick line).
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The RL final form *[kāk rī dó] (fig. 3; RL evaluation as in the two-stem eq. 61).
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Step witnesses #
In LR step 1, H-kāk deletes, since *TAUTDOCK and *CROWD block its dockings (60b).
In LR step 2, H-rī deletes, blocked by *CROWD (right), no-crossing (left) and *TAUTDOCK (own).
In LR step 3, H-dō deletes.
LR converges on attestedForm.
In RL step 1, the rightmost floating H (H-dō) deletes.
In RL step 2, the wrong-form seed, H-rī docks onto the now-uncrowded dō.
In RL step 3, H-kāk deletes.
In RL step 4, *FALL repairs dō's HM contour and MAX(H) ≫ MAX(M) deletes the M.
RL converges on starredForm.
LR and RL converge to distinct surface forms.
Regular HS: the divergent tie (eq. 62) #
The regular-HS derivation uses the same ranking with the count-based starFloatCount for
*FLOAT.
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The divergent tie ([Pru09]): the three single-deletion candidates all tie. (The paper's "no tie-breaker whatsoever helps" strengthening stays editorial.)
The regular-HS optimum has three elements.
The directional-LR optimum is a singleton.
Regular HS strictly underdetermines the step that directional HS decides.
Eq. (24): LR with *FALL repair #
Eq. (24) input /nãn + rī^H + nã/; H-rī is the only floating tone.
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The faithful candidate of the input.
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Directional-LR derivation over stdRanking.
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Attested [nãn rī ná]: H-rī docks onto nã, then *FALL repair deletes M-nã.
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In step 1, H-rī docks rightward onto nã (24d).
In step 2, *FALL repairs the contour by deleting M-nã, as MAX(H) ≫ MAX(M) (24g).
LR converges on attestedForm.
Eq. (21): phrase-final floating-H deletion #
Eq. (21) input /nãn + rī^H/ (phrase-final): no rightward landing site.
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The faithful candidate of the input.
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Directional-LR derivation; eq. (20)'s *FLOAT, *TAUTDOCK ≫ MAX(H) is a sub-ranking.
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Attested [nãn rī]: the floating H deletes.
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In step 1, H-rī deletes (21b).
LR converges on attestedForm (21d).
Eq. (27): *CROWD blocks docking onto an MH stem #
Eq. (27) input /kāk^H + kǎ/; kǎ carries a linked MH contour.
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The faithful candidate of the input.
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Directional-LR derivation over stdRanking.
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Attested [kāk kǎ]: H-kāk deletes; the MH contour survives.
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In step 1, H-kāk deletes, since *CROWD blocks docking onto the two-tone kǎ (27b).
LR converges on attestedForm (27e).
Eq. (30): *M◁L forces tautomorphemic docking #
Eq. (30) input /kāk^H + ìlí/; ìlí carries a linked LH contour (L% omitted).
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The faithful candidate of the input.
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Eq. (30) ranking: stdRanking plus *M◁L above *TAUTDOCK — the inversion that
licenses tautomorphemic docking (30c).
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- One or more equations did not get rendered due to their size.
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Attested [kǎk ìlí]: H-kāk docks onto its own TBU, making an MH contour.
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In step 1, the tone docks tautomorphemically, since deletion would create M◁L tier adjacency (30c).
LR converges despite the standing *TAUTDOCK violation (30e).
Eq. (22): HAVETONE drives docking onto a toneless stem #
Eq. (22a) input /nãn + rī^H + ne/; ne is toneless.
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The faithful candidate of the input.
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Directional-LR derivation over stdRanking.
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Attested [nãn rī né]: H-rī docks onto toneless ne.
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In step 1, H-rī docks onto ne, as HAVETONE prefers docking over deletion.
LR converges on attestedForm.
Deferred: GEN shift and insert-and-associate ops, L% boundary tone, §§3.3–3.4 tableaux #
Embed a Tone.overwrite output as a form with one morpheme m and links (i, i).
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- Autosegmental.Form.ofTBUList host m = Autosegmental.Form.melody m (List.map Tone.TBU.tone host) (List.map Tone.TBU.seg host) (List.map (fun (i : ℕ) => (i, i)) (List.range host.length)).toFinset
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The faithful candidate of an embedded form carries at most one surface tone per TBU.
A candidate with two surface tones on one TBU, which no faithful candidate of an
ofTBUList form has.