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2508.21186

Manifold Trajectories in Next-Token Prediction: From Replicator Dynamics to Softmax Equilibrium

Christopher R. Lee-Jenkins

wronghigh confidenceCounterexample detected
Category
math.DS
Journal tier
Note/Short/Other
Processed
Sep 28, 2025, 12:57 AM

Audit review

The paper asserts that for the replicator ODE ṗ_i = (1/T) p_i (s_i − s̄) with fixed scores s, the free energy F(p)=⟨p,s⟩+T H(p) is a Lyapunov function and that trajectories converge to the softmax π(s) (Theorem 4.1 and Proposition 3.7). However, under this ODE the explicit solution p_i(t)=p_i(0) e^{(s_i/T)t}/∑_j p_j(0) e^{(s_j/T)t} implies convergence to the argmax face, not to π(s); moreover, dF/dt is not sign-definite and can decrease (e.g., V=2, s=(0,1), T=1, p(0)=(1/2,1/2)). The paper conflates the natural-gradient of ⟨p,s⟩ (which yields the replicator field) with the natural-gradient of F (which yields the entropic/natural-gradient replicator). These claims in the paper are therefore false, while the model’s counterexample and corrected flow are correct. See the paper’s explicit claims in Theorem 4.1 and Proposition 3.7 for contrast .

Referee report (LaTeX)

\textbf{Recommendation:} reject

\textbf{Journal Tier:} note/short/other

\textbf{Justification:}

The main theorem (energy ascent of F and convergence to softmax under the replicator ODE with fixed scores) is incorrect. The proof conflates the natural gradient of ⟨p,s⟩ (which produces the replicator field) with the natural gradient of F=⟨p,s⟩+T H(p) (which would add an entropic term). As a result, the stated Lyapunov and convergence conclusions do not hold; in fact, trajectories converge to the argmax face, and F can decrease. The high-level idea is interesting, and with the correct ODE (entropic/natural-gradient replicator) the desired properties hold, but the current manuscript's core claims are false.