The claim

Two models of which of K perspectives governs each act y_{d,n} of an episode d:

  • H1, categorical. z_{d,n} ~ Cat(π) for one fixed π shared by every episode.
  • H2, LDA-style admixture (Blei, Ng and Jordan, LIT-1948). Each episode draws its own mixture θ_d ~ Dir(α), then z_{d,n} ~ Cat(θ_d). In smoothed LDA each topic’s distribution over outputs is an independent draw from one shared exchangeable Dirichlet, Dir(η) (§5.4), which is not the one at issue here.

What separates them is the per-episode mixture, as the owner said. The owner’s “the topics … are the dirichlet” names the wrong thing. The Dirichlet is a distribution over mixtures. The perspectives are the categories each mixture weights. A12’s parenthesis has the repair: “Strictly speaking, θ_d is the topic-mixture vector drawn from the Dirichlet; the topics are the categories it weights.”

Agreement within and across episodes. With α = (a, …, a), the moments of the Dirichlet give E[θ_k²] = a(a + 1)/(Ka(Ka + 1)). So

P(z_{d,1} = z_{d,2}) = Σ_k E[θ_k²] = (a + 1)/(Ka + 1),

while for acts in different episodes, whose mixtures are independent, P(z_{d,1} = z_{d’,1}) = Σ_k E[θ_k] E[θ’_k] = 1/K.

  • As a → 0 the within-episode agreement tends to 1: one perspective per episode. That is the mixture of unigrams, and persona selection read as selection.
  • As a → ∞ it tends to 1/K: every act an independent categorical draw, A12’s H1.

So the owner’s H1 has two readings, one draw per conversation or one per act, and they are the two limits of H2’s concentration. H2 is the family between them. The contrast is testable by within-episode against between-episode co-occurrence (QUESTION-370).

Checked by simulation (400,000 episodes each, 2026-11-02): K = 3, a = 1 gives 0.499 within against 0.5 predicted, and 0.3335 across against 1/3; K = 5, a = 0.2 gives 0.6002 against 0.6; K = 4, a = 10 gives 0.270 against 0.268.

What it does not say

  • That the hierarchy is what A12 said it is. A12 credited the 1/2 against 1/3 agreement (K = 3, a = 1) to “the hierarchy alone”. A single uncertain mixture shared by both draws, a Pólya urn with no hierarchy, gives the same 1/2. What makes LDA hierarchical is many episodes, each with its own θ_d, sharing α. Its signature is the within-against-between contrast, not the within-episode figure alone.
  • That an admixture is a feature allocation. CASE-165’s beta–Bernoulli model lets a member hold several features at once, and CLAIM-454’s “feature allocation” is that sense. An admixture puts one component behind each act. Which H2 the record means matters for QUESTION-276’s overlap requirement.
  • That an H2 fit is organization. An LDA’s components are exchangeable given θ_d (CLAIM-543), and its reinforcement of a run of choices is the observer’s learning (CLAIM-540).

Note of 2026-11-03: LDA and the Assistant Axis, read

The account of LDA matches the paper (NOTE-1519), which itself names the one-topic-per-document comparison (a “Dirichlet-multinomial clustering model”, p. 997; the mixture of unigrams, §4.2). The agreement formula was re-simulated. Two refinements: the symmetric a → 0 limit is the mixture of unigrams with uniform p(z), where the paper’s has a free p(z), the limit of Dir(sπ); and the a → ∞ limit is the paper’s unigram model once z is marginalized, so per-act independent personas are unidentifiable from one output distribution. And the Assistant Axis (NOTE-1505) finds the persona following the latest user message within a conversation (R² 0.53–0.77 against 0.10), neither limit: the switching model this claim’s defeater names. So persona selection read as one persona per conversation does not fit what either source describes. The derivation stands.