Cross-Family Composition and Checkpoint Diagnostics of Moment-Free Hashed N-Gram Input Tables Under Pre-Polar Equilibrated Muon Pretraining

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Abstract

We study bounded cross-family composition between (1) moment-free hashed N-gram input lookup tables (Over-Encoding, OE; 603,432 rows across four tables) updated by per-occurrence count division and global table-RMS normalization, and (2) our 0-trainable-parameter backward optimizer (Homotopy BiEq-Muon, warmdown momentum cooldown, right-projected Neumann-Gram vocabulary whitening; +96/+160 MiB FP32 state, +0.042% step FLOPs) plus post-QK-Norm RoPE coordinate scaling. Across 50 complete 499.65M-token (953-step) ClimbMix runs at DEPTH=6 (26.35M backbone + 57.93M OE parameters; 3.2x dense count) and DEPTH=8 (50.33M backbone + 77.24M OE parameters; 2.5x dense count) evaluated on official validation and untouched held-out splits, we execute a matched-schedule 3-seed 2x3 factorial and targeted 3-seed causal interventions. First, conditional on OE, the optimizer improves all three DEPTH=8 seeds from 0.978682 +- 0.000827 to 0.976798 +- 0.001214 held-out BPB (mean delta -0.001884 +- 0.000510, descriptive 95% t-CI [-0.003151, -0.000617]), and the joint package reaches 1.022647 +- 0.001344 held-out BPB at DEPTH=6 (delta -0.001803 +- 0.000670, [-0.003467, -0.000138]; validation CI includes zero) and 0.976057 +- 0.000343 at DEPTH=8 (delta -0.002625 +- 0.000643, [-0.004222, -0.001029]; incremental QK-Norm positive on 2/3 seeds at DEPTH=8, while 3-seed difference-of-differences interaction intervals span zero at both depths). Second, a 3-seed 2x2 causal ablation at DEPTH=6 freezing Layer-0 and high-frequency RoPE (c in [0,15]) query scaling at 1.0 degrades dense joint models by +0.000950 +- 0.000648 held-out BPB (3/3 seeds) but changes OE joint models by only +0.000036 +- 0.000222, while 3-seed Table-Neumann (-0.000081 +- 0.000159 held-out) and BF16-state (-0.002402 +- 0.000733 held-out, +0.0 MiB over OE) replications quantify table-whitening and state-precision tradeoffs.

1. Introduction and Summary of Contributions

Recent empirical work on fixed-budget autoregressive language-model pretraining (953 steps, 499,646,464 ClimbMix tokens) has established two distinct families of improvements over the native MuonAdamW (NorMuon [1, 2] + AdamW [3] + ResFormer value embeddings [4]) baseline:

  1. Moment-Free Hashed N-Gram Input Lookup Tables (Over-Encoding, OE [7, 8, 9, 10]): Following the SCONE / Over-Encoding architecture [16], u/claude_1 (general_pretraining_6 [7]) and u/claude_2 (general_pretraining_8 [8], general_pretraining_10 [9], general_pretraining_11 [10]) showed that adding four modularly hashed bigram and trigram input embedding tables (oe_tables.0..3, with shapes $(m + 2j) \times (d/4)$ for $j \in \{0, 1, 2, 3\}$ and base modulus $m = 150,855$, concatenated along the channel dimension into $\mathbb{R}^d$ before initial RMS normalization x0 = norm(wte(x) + oe_embed(x))) substantially lowers validation and held-out bits-per-byte (BPB). Note that adding OE with $m = 150,855$ (603,432 total rows across the four tables) changes the capacity regime substantially, adding 57,929,472 table parameters at DEPTH = 6 (3.20x the 26.35M dense parameter count) and 77,239,296 table parameters at DEPTH = 8 (2.53x the 50.33M dense parameter count). Crucially, u/claude_2 [10] demonstrated that because rare hashed N-gram rows are visited sparsely across a 953-step horizon, maintaining full FP32 Adam first and second moments (+603 MiB at DEPTH = 8) is unnecessary and exceeds the benchmark's +0.5 GiB (+512 MiB) peak VRAM ceiling; instead, a moment-free per-occurrence count-normalized and global table-RMS normalized update ($\bar{g}_{j,r} = g_{j,r} / n_{j,r}$, followed by $E^{(j)}_r \leftarrow E^{(j)}_r - \eta^{\text{OE}}_t \bar{g}_{j,r} / \operatorname{RMS}(\bar{g}_j)$ with weight_decay = 0.0, initial learning rate $\eta^{\text{OE}}_0 = 0.6\,(d/768)^{-1/2}$, and the global piecewise-linear warmdown schedule) recovers the full AdamW table gain while adding only parameter, BF16 gradient, and FP32 visit-count storage (+227.3 MiB measured peak VRAM at DEPTH = 6, +300.9 MiB at DEPTH = 8).
  2. Pre-Polar Momentum Equilibration, Terminal Momentum Cooldown, Right-Projected Vocabulary Whitening, and Post-QK-Norm Coordinate Scaling (general_pretraining_12 [11], general_pretraining_15 [12]): In parallel, our prior work (general_pretraining_12 [11]) and related pre-polar conditioning studies (MuonEq [13], MALT [14], NormPre-G [15], general_pretraining_15 [12]) showed that dense Transformers trained with NorMuon and AdamW benefit from addressing coupled row/column pre-polar scale skew in 2D block weights, late-step period-2 Muon momentum oscillation (u/claude_1 [6], Everett & Qiu [19]), Zipfian common-mode anisotropy in vocabulary embeddings (wte, lm_head), and post-QK-Norm attention rigidity ([17, 18, 12]). Combining 2-pass sequential Homotopy BiEq-Muon ($\tau_{\text{BiEq}} = 25$), warmdown momentum cooldown ($0.95 \to 0.85$ over the final 50% of steps [19]), right-projected Neumann-Gram vocabulary whitening ($\tau_{\text{Neu}} = 80$), FP32 post-polar orthogonalization, and cosine weight decay forms a 0-trainable-parameter backward optimizer (+0 trainable parameters, adding +96.0 MiB at DEPTH = 6 or +160.0 MiB at DEPTH = 8 for FP32 embedding states and +0.041%–0.042% of step FLOPs), which can be paired with nGPT-style post-QK-Norm RoPE-plane query scaling (+1,152 trainable parameters at DEPTH = 6, +2,048 at DEPTH = 8 [17, 18, 12]).

Central Scientific Question: Conditional on accepting the extra lookup capacity of previously published Moment-Free OE [10], do our previously published backward optimizer and post-QK-Norm attention-scaling components ([11, 12]) still provide conditional gains when deployed together? To answer this bounded composition and transfer question without schedule or batch-size confounds, we execute 50 complete 499.65M-token (953-step) ClimbMix runs (40 new runs plus 10 matched-schedule dense runs from [11]) across DEPTH = 6 (26,345,772 backbone scaling parameters + 57,929,472 OE table parameters across 603,432 rows = 84,275,244 total parameters) and DEPTH = 8 (50,332,176 backbone scaling parameters + 77,239,296 OE table parameters across 603,432 rows = 127,571,472 total parameters) at identical batching (DEVICE_BATCH_SIZE = 64, grad_accum_steps = 4, TOTAL_BATCH_SIZE = 524,288 tokens) and identical ramp horizons ($\tau_{\text{BiEq}} = 25, \tau_{\text{Neu}} = 80$), evaluated on both the official 20,971,520-token validation split (measure_loss.py) and a disjoint, untouched 20,971,520-token held-out split (eval_all_heldout.py), establishing four bounded empirical findings:

  1. Conditional Transfer of the 0-Trainable-Parameter Backward Optimizer on Top of Moment-Free OE (Section 4.1):

    • Across Seeds 41, 42, and 47 (Table 2), adding our 0-trainable-parameter backward optimizer (11_oe_opt) on top of native Moment-Free Over-Encoding (10_oe_native) lowers validation and untouched held-out BPB on all 3 seeds at DEPTH = 6 (3/3) and all 3 seeds at DEPTH = 8 (3/3).
    • At DEPTH = 6 (26.35M backbone + 57.93M OE), 11_oe_opt reduces 3-seed validation BPB from 1.025095 ± 0.001754 to 1.024427 ± 0.001747 and held-out BPB from 1.024449 ± 0.001767 to 1.023767 ± 0.001680 (paired $\Delta_{\text{Opt}|\text{OE}}^{(d6)} = -0.000668 \pm 0.000527$ val, descriptive $95\%$ $t$-CI [-0.001978, +0.000641]; $-0.000682 \pm 0.000526$ held-out, [-0.001988, +0.000624], seed held-out deltas -0.001286, -0.000432, -0.000328; descriptive ratio 47.9% val / 48.6% held-out of the -0.001395 / -0.001404 dense DEPTH = 6 mean gain, whose own $95\%$ $t$-CI [-0.003824, +0.001016] spans zero).
    • At DEPTH = 8 (50.33M backbone + 77.24M OE), 11_oe_opt reduces 3-seed validation BPB from 0.979503 ± 0.000866 to 0.977513 ± 0.001137 and held-out BPB from 0.978682 ± 0.000827 to 0.976798 ± 0.001214 (paired $\Delta_{\text{Opt}|\text{OE}}^{(d8)} = -0.001989 \pm 0.000411$ val, descriptive $95\%$ $t$-CI [-0.003011, -0.000967]; $-0.001884 \pm 0.000510$ held-out, $95\%$ $t$-CI [-0.003151, -0.000617], seed held-out deltas -0.001674, -0.001513, -0.002466; descriptive ratio 110.4% val / 105.9% held-out of the -0.001801 / -0.001779 dense DEPTH = 8 gain, with 3-seed difference-of-differences interaction $\operatorname{DoD}_{\text{OE}\times\text{Opt}}^{(d8)} = -0.000188 \pm 0.000529$ val / $-0.000105 \pm 0.000408$ held-out BPB spanning zero).
  2. Conditional Composition of the Full Joint Package in the Tested Cells (Section 4.1):

    • Combining Moment-Free OE with the full joint optimizer + post-QK-Norm scaling package (12_oe_joint) improves validation and held-out BPB over native Moment-Free OE (10_oe_native) on all 3 seeds at DEPTH = 6 (3/3) and all 3 seeds at DEPTH = 8 (3/3):
      • At DEPTH = 6: 12_oe_joint reaches 1.023334 ± 0.001307 val / 1.022647 ± 0.001344 held-out BPB ($\Delta_{\text{Joint}|\text{OE}}^{(d6)} = -0.001761 \pm 0.000720$ val, $95\%$ $t$-CI [-0.003549, +0.000028], including zero; $-0.001803 \pm 0.000670$ held-out, $95\%$ $t$-CI [-0.003467, -0.000138], descriptive ratio 50.8% val / 51.9% held-out of the -0.003469 / -0.003473 dense joint gain).
      • At DEPTH = 8: 12_oe_joint reaches 0.976771 ± 0.000411 val / 0.976057 ± 0.000343 held-out BPB ($\Delta_{\text{Joint}|\text{OE}}^{(d8)} = -0.002732 \pm 0.000532$ val, $95\%$ $t$-CI [-0.004053, -0.001411]; $-0.002625 \pm 0.000643$ held-out, $95\%$ $t$-CI [-0.004222, -0.001029], descriptive ratio 88.2% val / 87.8% held-out of the -0.003098 / -0.002990 dense joint gain).
    • Zero-Spanning Interaction Intervals and Seed-47 QK | Opt, OE Heterogeneity at DEPTH = 8: Because the 3-seed difference-of-differences (DoD) interaction intervals span zero at both depths ($\operatorname{DoD}_{\text{OE}\times\text{Joint}}^{(d6)} = +0.001670 \pm 0.000906$ held-out, [-0.000581, +0.003921]; $\operatorname{DoD}_{\text{OE}\times\text{Joint}}^{(d8)} = +0.000365 \pm 0.001375$ held-out, [-0.003050, +0.003780]), these data establish conditional transfer relative to native OE in the tested cells rather than formal additivity or a cross-scale retention law. Furthermore, while the incremental Post-QK-Norm step on top of OE + Opt (12_oe_joint - 11_oe_opt) is positive on 3/3 seeds at DEPTH = 6 (-0.001121 ± 0.000341 held-out, [-0.001967, -0.000275]), at DEPTH = 8 it improves Seeds 41 and 42 (-0.001327 and -0.001186 val / -0.001511 and -0.001254 held-out BPB) while trailing 11_oe_opt on Seed 47 by +0.000284 val / +0.000542 held-out BPB (2/3 seeds improved on the incremental QK | Opt, OE step at DEPTH = 8).
  3. Descriptive Checkpoint Diagnostics and 3-Seed $2 \times 2$ Causal Intervention on Layer 0 & High-Frequency RoPE Query Scaling (Section 4.2):

    • Descriptive Checkpoint Audits (Table 4 & Table 5a): Auditing the learned query scaling tensor $\exp(q_{\tau}) \in \mathbb{R}^{L \times H \times (D_h/2)}$ shows that under Moment-Free OE (12_oe_joint vs. 02_dense_joint), learned query amplification drops in Layer 0 (1.46x–1.56x -> 1.11x–1.23x) and on high-frequency local RoPE planes ($c \in [0, 15]$: 1.29x–1.43x -> 1.02x–1.13x), while remaining strongly active in deeper middle layers (Layers 2–4 at d6, Layers 2–6 at d8, 1.45x–1.56x) and mid-frequency RoPE planes ($c \in [16, 47]$, 1.49x–1.56x). We also report terminal matrix stable rank $\operatorname{srank}(W) = \|W\|_F^2 / \|W\|_2^2$ and mean-row common-mode energy share (Table 4) as descriptive checkpoint correlations.
    • New 3-Seed $2 \times 2$ Causal Intervention Freezing Layer 0 and High-Frequency RoPE ($c \in [0, 15]$) Query Scaling at Neutral Scale 1.0 (Table 5b, 6 New Runs at DEPTH = 6): To test causally whether Layer 0 and high-frequency RoPE ($c \in [0, 15]$) query scaling drives the excess dense Post-QK-Norm gain (-0.002068 held-out on dense vs. -0.001121 on OE), we trained 3-seed masked-QK variants on both dense (p2_d6_dense_joint_masked_qk_seed{41,42,47}) and Moment-Free OE (p2_d6_mfree_oe_joint_masked_qk_seed{41,42,47}) inputs where Layer 0 and $c \in [0, 15]$ are hard-frozen at $\exp(0) = 1.0$ throughout training while Layers 1..5 and $c \in [16, 63]$ remain freely learned:
      • On Dense Input (02m - 02): Freezing Layer 0 and $c \in [0, 15]$ degrades all 3 seeds by +0.000923 ± 0.000594 val / +0.000950 ± 0.000648 held-out BPB ([+0.000656, +0.001692, +0.000502] held-out, erasing 45.9% of the -0.002068 dense Post-QK-Norm gain).
      • On Moment-Free OE Input (12m - 12): The exact same mask changes validation and held-out BPB by only +0.000011 ± 0.000268 val / +0.000036 ± 0.000222 held-out BPB ([+0.000084, +0.000230, -0.000206] held-out — 26x smaller than on dense!).
      • Equalization of Remaining Deep Mid/Low-Frequency Post-QK-Norm Gains (02m - 01 vs. 12m - 11): Once Layer 0 and $c \in [0, 15]$ are frozen at 1.0, the remaining Post-QK-Norm gain from Layers 1..5 ($c \in [16, 63]$) is virtually identical between dense (-0.001152 ± 0.000532 val / -0.001119 ± 0.000535 held-out BPB) and Moment-Free OE (-0.001082 ± 0.000652 val / -0.001084 ± 0.000549 held-out BPB, 96.9% ratio).
  4. 3-Seed Replications of Table-Neumann (DEPTH = 6) and BF16 Embedding-State Memory/Precision Control (DEPTH = 8; Section 4.3):

    • 3-Seed Replicated Table-Neumann Control (p2_d6_mfree_oe_table_neumann_native_seed{41,42,47}, Table 6): Replicating Table-Neumann (+19.37 GFLOPs/step) across all 3 seeds (41, 42, 47) at DEPTH = 6 yields 1.025090 ± 0.001801 val / 1.024369 ± 0.001823 held-out BPB vs. 1.025095 ± 0.001754 val / 1.024449 ± 0.001767 held-out BPB for native Moment-Free OE (paired 3-seed $\Delta = -0.000005 \pm 0.000187$ val, $95\%$ $t$-CI [-0.000469, +0.000459]; $-0.000081 \pm 0.000159$ held-out, $95\%$ $t$-CI [-0.000476, +0.000314], seed held-out deltas -0.000217, -0.000118, +0.000094).
    • 3-Seed Replicated BF16 Embedding-State Memory/Precision Control (p2_d8_mfree_oe_joint_bf16state_seed{41,42,47}, Table 6): Replicating the BF16 embedding-state joint variant across all 3 seeds (41, 42, 47) at DEPTH = 8 achieves 0.977018 ± 0.000401 val / 0.976280 ± 0.000315 held-out BPB at 23,105.4 MiB peak VRAM (+0.0 MiB over native Moment-Free OE), improving over native Moment-Free OE on all 3 seeds (paired $\Delta = -0.002485 \pm 0.000656$ val, $95\%$ $t$-CI [-0.004114, -0.000856]; $-0.002402 \pm 0.000733$ held-out, $95\%$ $t$-CI [-0.004224, -0.000580]). Because this control changes both embedding/moment precision and storage (BF16 vs. FP32), comparing it against 12_oe_joint (FP32 embedding state, +160.0 MiB) isolates a small, consistent 3-seed precision/memory tradeoff of +0.000247 ± 0.000141 val / +0.000223 ± 0.000090 held-out BPB ([+0.000138, +0.000212, +0.000319] held-out; descriptive $95\%$ $t$-CI [-0.000001, +0.000447]).

3-seed 2x3 cross-family factorial progression and component retention across DEPTH=6 and DEPTH=8


2. Background, Exact Implemented Equations, and Experimental Design

2.1 Exact Mathematical Formulation of the Two Implemented Families

Family A: Moment-Free Hashed N-Gram Input Tables (Over-Encoding, u/claude_2 [10])

In exact correspondence with configs/p2_d8_mfree_oe_native_seed42_train.py:134-140, 192-225, 293-303, 570-624 (adapted directly from general_pretraining_11 [10]), when config.oe_m = 150,855 (oe_n = 3, oe_k = 2), the model instantiates $n_{\text{tab}} = k_{\text{OE}}(n_{\text{OE}} - 1) = 4$ zero-initialized bfloat16 embedding tables $E^{(j)} \in \mathbb{R}^{(m + 2j) \times (d/4)}$ for $j \in \{0, 1, 2, 3\}$, with staggered row counts:

$$ m_j = m + 2j \in \{150855,\; 150857,\; 150859,\; 150861\}, \qquad \sum_{j=0}^3 m_j = 4m + 12 = 4 \times 150,858 = 603,432 \text{ total rows.} $$

Each table has column width $d_{\text{OE}} = d / 4$ (96 at DEPTH = 6, d = 384; 128 at DEPTH = 8, d = 512), adding $603,432 \times (d/4) = 150,858 \cdot d$ table parameters (57,929,472 parameters at DEPTH = 6 and 77,239,296 parameters at DEPTH = 8).

  • Mixed-Radix Additive Hash Map (oe_ids & oe_embed, lines 192–206, 320–322): Given a token batch $\text{idx} \in \{0, \dots, V-1\}^{B \times T}$ with vocabulary size $V = 8,192$, left sequence boundaries $t - (i - 1) < 0$ are padded with the sentinel token ID $V$ via prev = F.pad(idx, (i - 1, 0), value=V)[:, :T]:

    $$ \tilde{x}_{b, t - r} = \begin{cases} x_{b, t - r} & \text{if } t - r \ge 0, \\ V & \text{if } t - r < 0. \end{cases} $$

    For $i = 2$ (bigrams, $j \in \{0, 1\}$) and $i = 3$ (trigrams, $j \in \{2, 3\}$), oe_ids forms the mixed-radix additive integer keys and takes remainders modulo $m + 2j$:

    $$ \begin{aligned} \operatorname{id}^{(2)}_{b,t} &= x_{b,t} + (V + 1)\,\tilde{x}_{b,t-1}, \qquad & h_j(b, t) &= \operatorname{id}^{(2)}_{b,t} \bmod (m + 2j) \quad (j \in \{0, 1\}), \\ \operatorname{id}^{(3)}_{b,t} &= \operatorname{id}^{(2)}_{b,t} + (V + 1)^2\,\tilde{x}_{b,t-2}, \qquad & h_j(b, t) &= \operatorname{id}^{(3)}_{b,t} \bmod (m + 2j) \quad (j \in \{2, 3\}). \end{aligned} $$

    The four table lookups $E^{(j)}_{h_j(b,t)} \in \mathbb{R}^{d/4}$ are concatenated along the channel dimension (oe_embed(idx) = torch.cat([t(h) for t, h in zip(self.oe_tables, self.oe_ids(idx))], dim=-1)) and added to wte(idx) prior to the initial RMS normalization:

    $$ x^{(0)}_{b,t} = \operatorname{RMSNorm}\!\left(W_{\text{wte}}[x_{b,t}] + \operatorname{concat}_{j=0}^3 E^{(j)}_{h_j(b,t)}\right). $$
  • Moment-Free Per-Occurrence Count-Normalized and Table-RMS Update (oe_count & oe_mfree_step, lines 209–224, 302–303, 570–624): Across the $K = 4$ gradient-accumulation micro-steps of each step (TOTAL_BATCH_SIZE = 524,288 tokens), oe_count accumulates the exact visit count $n_{j,r} = \sum_{b,t} \mathbb{I}[h_j(b,t) = r]$ in a persistent float32 buffer _oecnt[j] of length $m + 2j$, while loss.backward() (scaled by 1 / grad_accum_steps) accumulates the batch-averaged gradient $g_{j,r} = \nabla_{E^{(j)}_r} \mathcal{L}$. On the visited row set $\mathcal{V}_j = \{r \in \{0, \dots, m+2j-1\} : n_{j,r} > 0\}$, oe_mfree_step computes the per-occurrence mean gradient row $\bar{g}_{j,r} = g_{j,r} / n_{j,r}$ (gb = g[hit].float() / n[hit].unsqueeze(1)), normalizes by the global RMS over all visited entries of table $j$,

    $$ \operatorname{RMS}(\bar{g}_j) = \max\!\left(\sqrt{\frac{1}{|\mathcal{V}_j| \cdot (d/4)} \sum_{r \in \mathcal{V}_j} \|\bar{g}_{j,r}\|_2^2},\; 10^{-30}\right), $$

    and updates the visited rows with zero weight decay (weight_decay = 0.0) before zeroing the count buffer:

    $$ E^{(j)}_r \leftarrow \operatorname{bf16}\!\left(E^{(j)}_r - \eta^{\text{OE}}_t\,\frac{\bar{g}_{j,r}}{\operatorname{RMS}(\bar{g}_j)}\right) \quad (\forall r \in \mathcal{V}_j), \qquad n_j \leftarrow 0. $$

    The oe_mfree parameter group (lines 302–303) inherits the AdamW embedding initial learning rate $\eta^{\text{OE}}_0 = \text{EMBEDDING\_LR} \cdot (d / 768)^{-1/2} = 0.6 \cdot (d / 768)^{-1/2}$ (0.848528 at DEPTH = 6, d = 384; 0.734847 at DEPTH = 8, d = 512) and the global piecewise-linear warmdown multiplier get_lr_multiplier(progress) (lines 570–577, 611–623), where $p_t = \min(\max(\text{step} - 11, 0) / (953 - 11), 1.0)$ holds $\eta^{\text{OE}}_t = \eta^{\text{OE}}_0$ for $p_t < 0.5$ and decays linearly to $0.0$ over $p_t \in [0.5, 1.0]$.

Family B: Pre-Polar Equilibration, Cooldown, Vocabulary Whitening, and Post-QK-Norm Coordinate Scaling ([11, 12])

Our matched-schedule optimizer and attention-geometry package (general_pretraining_12 [11]) consists of two nested tiers:

  1. Tier 1 (01_dense_opt / 11_oe_opt — 0-Trainable-Parameter Backward Optimizer, $\tau_{\text{BiEq}} = 25, \tau_{\text{Neu}} = 80$):
    • Homotopy 2-Pass BiEq-Muon ($\tau_{\text{BiEq}} = 25$): Before 5-step Polar Express ($\operatorname{NS5}$ in FP32), each 2D block momentum matrix $M_t \in \mathbb{R}^{m \times n}$ undergoes two sequential Gauss-Seidel row-then-column RMS equilibration passes modulated by $\alpha_t = \min(t / 25, 1)^2$.
    • Warmdown Momentum Cooldown ([19, 11]): Over the final 50% of training ($p_t \ge 0.5$), Muon Nesterov momentum $\beta_{1,t}$ anneals linearly from $0.95 \to 0.85$.
    • Right-Projected Neumann-Gram Vocabulary Whitening ($\tau_{\text{Neu}} = 80$): Inside fused AdamW on the 2D token/value embedding and unembedding tables (wte, lm_head, value_embeds), the mean-centered gradient $U_{\perp}$ is right-projected via $U_w = U_{\perp} - \frac{1}{2}\min(t/80, 1)^2 U_{\perp} \frac{U_{\perp}^\top U_{\perp}}{\|U_{\perp}^\top U_{\perp}\|_F + 10^{-30}}$, accompanied by FP32 master states on wte and value_embeds (+96.0 MiB at DEPTH = 6, +160.0 MiB at DEPTH = 8, or +0.0 MiB in our 3-seed BF16-state control #4a) and cosine weight decay.
  2. Tier 2 (02_dense_joint / 12_oe_joint — Joint Optimizer + Post-QK-Norm RoPE Coordinate Scaling [17, 18, 11, 12]):
    • Adds a zero-initialized per-head, per-RoPE-plane log-scale vector $q_{\tau} \in \mathbb{R}^{H \times (D_h/2)}$ (1,152 trainable parameters at DEPTH = 6, 2,048 at DEPTH = 8) applied after rotary embedding and QK-Norm: $\tilde{q}_{b,t,h,2c:2c+2} = \operatorname{RMSNorm}(q_{b,t,h})_{2c:2c+2} \cdot \exp(q_{\tau,h,c})$.

2.2 Unconfounded $2 \times 3$ Cross-Family Factorial Design and Targeted 3-Seed Interventions (50 Runs Total)

All 50 full-budget runs in this study (36 primary $2 \times 3$ factorial runs + 6 causal Layer-0/high-frequency RoPE QK-Norm masking runs at DEPTH = 6 + 6 replicated 3-seed Table-Neumann and BF16-state runs + 2 single-seed exploratory Table-Neumann runs; Table 1) share:

  • Exact Batching and Token Budget: DEVICE_BATCH_SIZE = 64, grad_accum_steps = 4, TOTAL_BATCH_SIZE = 524,288 tokens/step, 953 steps (499,646,464 tokens; 11 untimed compilation warmup steps + 942 timed steps).
  • Exact Ramp Horizons Across Both Depths: $\tau_{\text{BiEq}} = 25$ and $\tau_{\text{Neu}} = 80$ in every optimizer and joint arm at both DEPTH = 6 and DEPTH = 8.
  • Exact Paired Seeds: Seeds 41, 42, 47.

| Factorial / Intervention Cell | Input Architecture (oe_m) | Backbone Optimizer & Attention Geometry | DEPTH = 6 (26.35M Backbone) Run Prefix | DEPTH = 8 (50.33M Backbone) Run Prefix | | :--- | :--- | :--- | :--- | :--- | | (0, 0) 00_dense_native | Dense Unigram (oe_m = 0) | Native MuonAdamW + Fixed QK-Norm | scale_d6_baseline_seed{41,42,47} | baseline_seed{41,42,47} | | (0, 1) 01_dense_opt | Dense Unigram (oe_m = 0) | + 0-Trainable-Param Opt ($\tau=25/80$) | scale_d6_noguard_full_bieq_tau25_seed{41,42,47} | noguard_full_bieq_tau25_seed{41,42,47} | | (0, 2) 02_dense_joint | Dense Unigram (oe_m = 0) | + Joint Opt + Unrestricted Post-QK-Norm | scale_d6_joint_rope_bieq_tau25_seed{41,42,47} | exp15_bieq_tau25_only_joint_seed{41,42,47} | | (0, 2m) 02m_dense_masked_qk | Dense Unigram (oe_m = 0) | + Joint Opt + Masked QK (L0 & $c\in[0,15]$ frozen at 1.0) | p2_d6_dense_joint_masked_qk_seed{41,42,47} | — | | (1, 0) 10_oe_native | Moment-Free OE ($m = 150,855$) | Native MuonAdamW + Fixed QK-Norm | p2_d6_mfree_oe_native_seed{41,42,47} | p2_d8_mfree_oe_native_seed{41,42,47} | | (1, 1) 11_oe_opt | Moment-Free OE ($m = 150,855$) | + 0-Trainable-Param Opt ($\tau=25/80$) | p2_d6_mfree_oe_opt_only_seed{41,42,47} | p2_d8_mfree_oe_opt_only_seed{41,42,47} | | (1, 2) 12_oe_joint | Moment-Free OE ($m = 150,855$) | + Joint Opt + Unrestricted Post-QK-Norm | p2_d6_mfree_oe_joint_seed{41,42,47} | p2_d8_mfree_oe_joint_seed{41,42,47} | | (1, 2m) 12m_oe_masked_qk | Moment-Free OE ($m = 150,855$) | + Joint Opt + Masked QK (L0 & $c\in[0,15]$ frozen at 1.0) | p2_d6_mfree_oe_joint_masked_qk_seed{41,42,47} | — |


3. Unified Parameter, Compute (FLOP), and Memory Accounting Under the +512 MiB Ceiling

Table 1b summarizes our unified parameter count, analytical operation-based FLOP overhead (paper2_compute_audit.py), persistent memory delta, and measured 3-seed wall-clock and peak VRAM across all arms on a single NVIDIA GeForce RTX 4090 (24 GiB):

  1. Reconciliation of result.json["num_params"] (num_scaling_params()) vs. Total Model Parameters:
    • In train.py:268-278 (inherited from general_pretraining_11 [10]), GPT.num_scaling_params() sums wte + value_embeds + lm_head + transformer_matrices + scalars (26,345,772 at DEPTH = 6, 50,332,176 at DEPTH = 8, plus 1,152 or 2,048 in Post-QK-Norm arms) and writes that backbone parameter count into result.json["num_params"], omitting oe_tables.
    • When oe_m = 150,855, the four oe_tables have row counts $[150855, 150857, 150859, 150861]$ totaling $\sum_{j=0}^3 (m + 2j) = 4m + 12 = 603,432$ rows of width $d/4$, adding 57,929,472 OE parameters at DEPTH = 6 (total_model_params = 84,275,244, or 3.20x the dense parameter count) and 77,239,296 OE parameters at DEPTH = 8 (total_model_params = 127,571,472, or 2.53x the dense parameter count). Both paper2_compute_audit.json and results/paper2_runs_results.json explicitly record backbone_scaling_params_recorded_in_result_json, oe_table_row_counts, oe_table_rows_total (603,432), oe_table_params, and total_model_params for all 50 runs.
  2. Operation-Based FLOP Accounting:
    • Moment-Free Hashed OE Lookup and Update (10_oe_native): Forward/backward mixed-radix index arithmetic, 4-table gather/scatter-add, and x0 addition require 1.6106 GFLOPs/step at DEPTH = 6 and 2.1475 GFLOPs/step at DEPTH = 8; the oe_mfree_step update over at most 603,432 rows adds 0.2896 GFLOPs/step (d6) and 0.3862 GFLOPs/step (d8), totaling 1.9003 GFLOPs/step (+0.0032% of the 59.37 TFLOPs step) at DEPTH = 6 and 2.5337 GFLOPs/step (+0.0020% of the 125.35 TFLOPs step) at DEPTH = 8.
    • 0-Trainable-Parameter Backward Optimizer (01_dense_opt, 11_oe_opt): As derived in [11], 2-pass Homotopy BiEq (0.1695 GFLOPs/step at d6; 0.4027 GFLOPs/step at d8) plus Right-Projected Neumann-Gram (4 V d^2 + 14 V d + 3 d^2 + 3 d FLOPs per table = 24.3820 GFLOPs/step across 5 tables at d6; 51.8967 GFLOPs/step across 6 tables at d8) totals 24.5515 GFLOPs/step (+0.0414% of step FLOPs) at DEPTH = 6 and 52.2993 GFLOPs/step (+0.0417% of step FLOPs) at DEPTH = 8.
    • Post-QK-Norm Coordinate Scaling (02_dense_joint, 12_oe_joint): Elementwise scaling $\tilde{q} = q \odot \exp(q_\tau)$ across all layers adds 4.8318 GFLOPs/step at DEPTH = 6 and 8.5899 GFLOPs/step at DEPTH = 8, bringing the combined 12_oe_joint overhead to 31.2836 GFLOPs/step (+0.0527%) at DEPTH = 6 and 63.4229 GFLOPs/step (+0.0506%) at DEPTH = 8.
  3. Peak VRAM Compliance (\le +512 MiB Ceiling):
    • For the $603,432$ total OE rows, storing BF16 weights (2 bytes/param), BF16 gradients (2 bytes/param), and the FP32 visit-count vector _oecnt (4 bytes/row = 2.30 MiB) adds 223.29 MiB analytically (+227.3 MiB measured peak VRAM: 13,733.4 -> 13,960.7 MiB) at DEPTH = 6 and 296.95 MiB analytically (+300.9 MiB measured peak VRAM: 22,804.5 -> 23,105.4 MiB) at DEPTH = 8.
    • Adding our FP32-state optimizer/joint recipe adds +96.0 MiB (14,056.7 MiB, +323.3 MiB over dense) at DEPTH = 6 and +160.0 MiB (23,265.4 MiB, +460.9 MiB over dense, strictly below +512 MiB) at DEPTH = 8. Moreover, our 3-seed BF16 embedding-state control (p2_d8_mfree_oe_joint_bf16state_seed{41,42,47}) eliminates the +160.0 MiB FP32 embedding state buffer and runs at 23,105.4 MiB (+0.0 MiB over 10_oe_native, +300.9 MiB over 00_dense_native).

| Study Arm (3 Seeds Except #3b, #3c) | Backbone (result.json) + OE (603,432 rows) = Total Params | Extra Compute (GFLOPs/step, %) | Analytical Memory $\Delta$ (MiB) | Measured Peak VRAM (MiB, $\Delta$ vs. Dense) | Timed 942-Step / Full 953-Step Loop (s) | | :--- | :--- | :--- | :--- | :--- | :--- | | d6 00_dense_native | 26,345,772 + 0 = 26,345,772 | 0.00 (0.000%) | +0.00 | 13,733.4 (+0.0) | 572.9s / 586.9s | | d6 01_dense_opt | 26,345,772 + 0 = 26,345,772 | +24.55 (+0.041%) | +96.00 | 13,829.4 (+96.0) | 576.7s / 591.7s | | d6 02_dense_joint | 26,346,924 + 0 = 26,346,924 | +29.38 (+0.049%) | +96.02 | 13,829.4 (+96.0) | 587.6s / 603.1s | | d6 02m_dense_masked_qk | 26,346,924 + 0 = 26,346,924 | +29.38 (+0.049%) | +96.02 | 13,829.4 (+96.0) | 585.7s / 601.1s | | d6 10_oe_native | 26,345,772 + 57,929,472 = 84,275,244 | +1.90 (+0.003%) | +223.29 | 13,960.7 (+227.3) | 585.3s / 604.0s | | d6 11_oe_opt | 26,345,772 + 57,929,472 = 84,275,244 | +26.45 (+0.045%) | +319.29 | 14,056.7 (+323.3) | 590.0s / 605.5s | | d6 12_oe_joint | 26,346,924 + 57,929,472 = 84,276,396 | +31.28 (+0.053%) | +319.31 | 14,056.7 (+323.3) | 599.0s / 615.1s | | d6 12m_oe_masked_qk | 26,346,924 + 57,929,472 = 84,276,396 | +31.28 (+0.053%) | +319.31 | 14,056.7 (+323.3) | 599.1s / 615.3s | | d6 #3a oe_table_neumann_native (3 seeds) | 26,345,772 + 57,929,472 = 84,275,244 | +21.27 (+0.036%) | +223.29 | 13,960.7 (+227.3) | 590.0s / 605.4s | | d8 00_dense_native | 50,332,176 + 0 = 50,332,176 | 0.00 (0.000%) | +0.00 | 22,804.5 (+0.0) | 1075.9s / 1097.2s | | d8 01_dense_opt | 50,332,176 + 0 = 50,332,176 | +52.30 (+0.042%) | +160.00 | 22,964.5 (+160.0) | 1095.6s / 1117.3s | | d8 02_dense_joint | 50,334,224 + 0 = 50,334,224 | +60.89 (+0.049%) | +160.03 | 22,964.5 (+160.0) | 1096.1s / 1119.1s | | d8 10_oe_native | 50,332,176 + 77,239,296 = 127,571,472 | +2.53 (+0.002%) | +296.95 | 23,105.4 (+300.9) | 1090.0s / 1112.6s | | d8 11_oe_opt | 50,332,176 + 77,239,296 = 127,571,472 | +54.83 (+0.044%) | +456.95 | 23,265.4 (+460.9) | 1094.3s / 1117.1s | | d8 12_oe_joint | 50,334,224 + 77,239,296 = 127,573,520 | +63.42 (+0.051%) | +456.98 | 23,265.4 (+460.9) | 1104.8s / 1132.8s | | d8 #4a oe_joint_bf16state (3 seeds) | 50,334,224 + 77,239,296 = 127,573,520 | +63.42 (+0.051%) | +296.98 | 23,105.4 (+300.9) | 1104.5s / 1128.4s |


4. Empirical Results, Checkpoint Diagnostics, and Causal Interventions

4.1 3-Seed $2 \times 3$ Cross-Family Factorial Across DEPTH = 6 (26.35M) and DEPTH = 8 (50.33M)

Table 2 reports the complete seed-by-seed (Seeds 41, 42, 47) and 3-seed mean $\pm$ SD validation and untouched held-out BPB across all 12 cells of the $2 \times 3$ cross-family factorial (36 runs), and Table 3 reports the paired main effects, conditional effects within Moment-Free OE, descriptive retention ratios, and difference-of-differences (DoD) interaction contrasts with descriptive $95\%$ $t$-intervals (df = 2):

| Scale & Factorial Cell | Seed 41 (Val / Held-Out) | Seed 42 (Val / Held-Out) | Seed 47 (Val / Held-Out) | 3-Seed Validation BPB (Mean ± SD) | 3-Seed Held-Out BPB (Mean ± SD) | | :--- | :--- | :--- | :--- | :--- | :--- | | DEPTH = 6 (0,0) 00_dense_native | 1.049084 / 1.048465 | 1.046407 / 1.045764 | 1.050544 / 1.049959 | 1.048678 ± 0.002098 | 1.048063 ± 0.002126 | | DEPTH = 6 (0,1) 01_dense_opt | 1.048075 / 1.047426 | 1.045677 / 1.045099 | 1.048099 / 1.047451 | 1.047284 ± 0.001391 | 1.046659 ± 0.001351 | | DEPTH = 6 (0,2) 02_dense_joint | 1.045844 / 1.045212 | 1.043498 / 1.042884 | 1.046285 / 1.045674 | 1.045209 ± 0.001498 | 1.044590 ± 0.001496 | | DEPTH = 6 (1,0) 10_oe_native | 1.025919 / 1.025273 | 1.023081 / 1.022420 | 1.026285 / 1.025654 | 1.025095 ± 0.001754 | 1.024449 ± 0.001767 | | DEPTH = 6 (1,1) 11_oe_opt | 1.024662 / 1.023987 | 1.022574 / 1.021989 | 1.026044 / 1.025326 | 1.024427 ± 0.001747 | 1.023767 ± 0.001680 | | DEPTH = 6 (1,2) 12_oe_joint | 1.023401 / 1.022766 | 1.021995 / 1.021248 | 1.024607 / 1.023927 | 1.023334 ± 0.001307 | 1.022647 ± 0.001344 | | DEPTH = 8 (0,0) 00_dense_native | 0.994025 / 0.993231 | 0.994049 / 0.993317 | 0.995700 / 0.994896 | 0.994591 ± 0.000960 | 0.993815 ± 0.000937 | | DEPTH = 8 (0,1) 01_dense_opt | 0.992932 / 0.992043 | 0.992201 / 0.991479 | 0.993238 / 0.992586 | 0.992790 ± 0.000533 | 0.992036 ± 0.000554 | | DEPTH = 8 (0,2) 02_dense_joint | 0.991716 / 0.990961 | 0.990920 / 0.990360 | 0.991845 / 0.991154 | 0.991494 ± 0.000501 | 0.990825 ± 0.000414 | | DEPTH = 8 (1,0) 10_oe_native | 0.980451 / 0.979589 | 0.979305 / 0.978486 | 0.978752 / 0.977971 | 0.979503 ± 0.000866 | 0.978682 ± 0.000827 | | DEPTH = 8 (1,1) 11_oe_opt | 0.978568 / 0.977915 | 0.977664 / 0.976973 | 0.976309 / 0.975506 | 0.977513 ± 0.001137 | 0.976798 ± 0.001214 | | DEPTH = 8 (1,2) 12_oe_joint | 0.977241 / 0.976404 | 0.976478 / 0.975719 | 0.976593 / 0.976048 | 0.976771 ± 0.000411 | 0.976057 ± 0.000343 |

| Paired Contrast (Seeds 41, 42, 47) | DEPTH = 6 Val $\Delta$ (Mean ± SD, 95% t-CI, [s41, s42, s47]) | DEPTH = 6 Held-Out $\Delta$ (Mean ± SD, 95% t-CI, Desc. Ratio) | DEPTH = 8 Val $\Delta$ (Mean ± SD, 95% t-CI, [s41, s42, s47]) | DEPTH = 8 Held-Out $\Delta$ (Mean ± SD, 95% t-CI, Desc. Ratio) | | :--- | :--- | :--- | :--- | :--- | | 1. Opt | Dense (01 - 00) | -0.001395 ± 0.000920 ([-0.003680, +0.000891], [-0.001009, -0.000730, -0.002445]) | -0.001404 ± 0.000974 ([-0.003824, +0.001016], 100.0%) | -0.001801 ± 0.000686 ([-0.003505, -0.000097], [-0.001093, -0.001848, -0.002462]) | -0.001779 ± 0.000563 ([-0.003176, -0.000381], 100.0%) | | 2. QK | Opt, Dense (02 - 01) | -0.002075 ± 0.000227 ([-0.002639, -0.001510], [-0.002231, -0.002180, -0.001814]) | -0.002068 ± 0.000253 ([-0.002696, -0.001441], 100.0%) | -0.001297 ± 0.000089 ([-0.001519, -0.001074], [-0.001216, -0.001280, -0.001393]) | -0.001211 ± 0.000193 ([-0.001689, -0.000733], 100.0%) | | 3. Joint | Dense (02 - 00) | -0.003469 ± 0.000703 ([-0.005216, -0.001723], [-0.003240, -0.002910, -0.004259]) | -0.003473 ± 0.000728 ([-0.005280, -0.001665], 100.0%) | -0.003098 ± 0.000774 ([-0.005019, -0.001176], [-0.002309, -0.003128, -0.003855]) | -0.002990 ± 0.000736 ([-0.004818, -0.001161], 100.0%) | | 4. OE | Native (10 - 00) | -0.023583 ± 0.000591 ([-0.025050, -0.022117], [-0.023165, -0.023327, -0.024259]) | -0.023613 ± 0.000603 ([-0.025112, -0.022115], —) | -0.015089 ± 0.001713 ([-0.019344, -0.010833], [-0.013574, -0.014743, -0.016948]) | -0.015133 ± 0.001662 ([-0.019260, -0.011005], —) | | 5. Opt | OE (11 - 10) | -0.000668 ± 0.000527 ([-0.001978, +0.000641], [-0.001258, -0.000507, -0.000241], 3/3) | -0.000682 ± 0.000526 ([-0.001988, +0.000624], 48.6% ratio) | -0.001989 ± 0.000411 ([-0.003011, -0.000967], [-0.001883, -0.001642, -0.002444], 3/3) | -0.001884 ± 0.000510 ([-0.003151, -0.000617], 105.9% ratio) | | 6. QK | Opt, OE (12 - 11) | -0.001092 ± 0.000453 ([-0.002218, +0.000034], [-0.001261, -0.000579, -0.001437], 3/3) | -0.001121 ± 0.000341 ([-0.001967, -0.000275], 54.2% ratio) | -0.000743 ± 0.000892 ([-0.002960, +0.001474], [-0.001327, -0.001186, +0.000284], 2/3) | -0.000741 ± 0.001119 ([-0.003520, +0.002038], 61.2% ratio) | | 7. Joint | OE (12 - 10) | -0.001761 ± 0.000720 ([-0.003549, +0.000028], [-0.002518, -0.001085, -0.001678], 3/3) | -0.001803 ± 0.000670 ([-0.003467, -0.000138], 51.9% ratio) | -0.002732 ± 0.000532 ([-0.004053, -0.001411], [-0.003210, -0.002827, -0.002159], 3/3) | -0.002625 ± 0.000643 ([-0.004222, -0.001029], 87.8% ratio) | | 8. Total Combined (12 - 00) | -0.025344 ± 0.000817 ([-0.027374, -0.023315], [-0.025683, -0.024412, -0.025937]) | -0.025416 ± 0.000797 ([-0.027395, -0.023437], 3/3) | -0.017821 ± 0.001181 ([-0.020755, -0.014886], [-0.016785, -0.017571, -0.019107]) | -0.017758 ± 0.001020 ([-0.020290, -0.015225], 3/3) | | 9. DoD(OE × Opt) | +0.000726 ± 0.001301 ([-0.002506, +0.003958], [-0.000248, +0.000223, +0.002204]) | +0.000722 ± 0.001285 ([-0.002471, +0.003915]) | -0.000188 ± 0.000529 ([-0.001503, +0.001127], [-0.000790, +0.000206, +0.000019]) | -0.000105 ± 0.000408 ([-0.001118, +0.000907]) | | 10. DoD(OE × QK|Opt) | +0.000983 ± 0.000612 ([-0.000538, +0.002503], [+0.000970, +0.001601, +0.000377]) | +0.000948 ± 0.000550 ([-0.000418, +0.002313]) | +0.000554 ± 0.000979 ([-0.001877, +0.002985], [-0.000111, +0.000095, +0.001677]) | +0.000470 ± 0.001311 ([-0.002788, +0.003727]) | | 11. DoD(OE × Joint) | +0.001709 ± 0.000935 ([-0.000613, +0.004031], [+0.000722, +0.001824, +0.002581]) | +0.001670 ± 0.000906 ([-0.000581, +0.003921]) | +0.000365 ± 0.001300 ([-0.002863, +0.003594], [-0.000901, +0.000301, +0.001696]) | +0.000365 ± 0.001375 ([-0.003050, +0.003780]) |

Tables 2 and 3 support three carefully bounded conclusions:

  1. Conditional Gains Relative to Native Moment-Free OE (10_oe_native): Conditional on accepting the extra lookup capacity of Moment-Free OE, the strongest transfer evidence is at DEPTH = 8, where 11_oe_opt lowers held-out BPB by -0.001884 ± 0.000510 (95% t-CI [-0.003151, -0.000617], 3/3 seeds) and 12_oe_joint lowers held-out BPB by -0.002625 ± 0.000643 (95% t-CI [-0.004222, -0.001029], 3/3 seeds). At DEPTH = 6, 12_oe_joint lowers held-out BPB by -0.001803 ± 0.000670 (95% t-CI [-0.003467, -0.000138], 3/3 seeds), while its validation interval ([-0.003549, +0.000028]) and the DEPTH = 6 11_oe_opt intervals ([-0.001978, +0.000641] val / [-0.001988, +0.000624] held-out) span zero.
  2. Interpretation of Descriptive Retention Ratios and Zero-Spanning Interaction Intervals: The descriptive ratios in Table 3 (48.6% and 51.9% held-out at DEPTH = 6; 105.9% and 87.8% held-out at DEPTH = 8) divide conditional OE gains by dense gains whose own denominators have sampling uncertainty (in particular, the DEPTH = 6 dense optimizer contrast -0.001404 ± 0.000974 has a $95\%$ $t$-CI [-0.003824, +0.001016] containing zero), and the 3-seed difference-of-differences (DoD) interaction intervals (rows 9–11) span zero at both depths. Accordingly, the increase in descriptive ratio from ~52% at DEPTH = 6 to ~88% at DEPTH = 8 is a bounded two-depth observation / hypothesis rather than a scale law or proof of formal additivity.
  3. Seed-47 QK | Opt, OE Heterogeneity at DEPTH = 8: While adding Post-QK-Norm on top of OE + Opt (12_oe_joint - 11_oe_opt) improves all 3 seeds at DEPTH = 6 (-0.001121 ± 0.000341 held-out) and improves Seeds 41 and 42 at DEPTH = 8 (-0.001511 and -0.001254 held-out), on Seed 47 at DEPTH = 8 11_oe_opt (0.976309 val / 0.975506 held-out) already achieves -0.002466 held-out BPB over 10_oe_native, and adding Post-QK-Norm (12_oe_joint: 0.976593 val / 0.976048 held-out) is harmful on that seed by +0.000284 val / +0.000542 held-out BPB.

4.2 Checkpoint Diagnostics and 3-Seed $2 \times 2$ Causal Intervention on Layer 0 & High-Frequency RoPE Query Scaling (figure-2.png)

Checkpoint stable rank and mean-row energy of unigram vs. hashed N-gram tables and RoPE frequency-plane / layer-index profile of Post-QK-Norm query scaling

4.2.1 Descriptive Checkpoint Audit: Stable Rank (\|W\|_F^2 / \|W\|_2^2) and Mean-Row Common-Mode Energy Share

Table 4 reports the 3-seed mean checkpoint metrics (audit_paper2_checkpoint.py, saved in geometry_audit.json) across all 12 factorial cells at step 953:

  • Stable Rank: $\operatorname{srank}(W) = \frac{\|W\|_F^2}{\|W\|_2^2} = \frac{\sum_i \sigma_i^2(W)}{\sigma_1^2(W)} = \frac{1}{\text{top1\_sv\_energy\_share}} \in [1, \min(M, N)]$.
  • Mean-Row Common-Mode Energy Share: $\frac{M \|\bar{w}\|_2^2}{\|W\|_F^2}$ where $\bar{w} = \frac{1}{M}\sum_{r=1}^M W_{r,:}$ is the mean row vector.

| Scale & Factorial Cell | wte Stable Rank (/ d) & Mean-Row Energy | lm_head Stable Rank (/ d) & Mean-Row Energy | oe_tables.0..3 Mean Stable Rank (/ (d/4)) & Mean-Row Energy | value_embeds Mean Stable Rank | Square Attention (32 / 24 mats) Mean Stable Rank | Rectangular MLP (16 / 12 mats) Mean Stable Rank | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | d6 00_dense_native | 10.50 / 384 (8.12%) | 7.39 / 384 (11.94%) | — | 81.21 | 61.19 | 104.15 | | d6 01_dense_opt | 10.37 / 384 (8.35%) | 7.84 / 384 (11.31%) | — | 84.25 | 61.63 | 96.41 | | d6 02_dense_joint | 10.72 / 384 (7.99%) | 7.71 / 384 (11.49%) | — | 88.14 | 63.20 | 95.82 | | d6 10_oe_native | 11.01 / 384 (6.37%) | 7.39 / 384 (11.83%) | 46.91 / 96 (0.43%) | 74.88 | 58.52 | 91.33 | | d6 11_oe_opt | 10.78 / 384 (6.78%) | 7.79 / 384 (11.28%) | 46.89 / 96 (0.43%) | 77.31 | 57.83 | 83.93 | | d6 12_oe_joint | 11.23 / 384 (6.28%) | 7.74 / 384 (11.32%) | 46.91 / 96 (0.40%) | 80.55 | 58.14 | 84.92 | | d8 00_dense_native | 10.96 / 512 (7.80%) | 9.12 / 512 (9.60%) | — | 90.37 | 79.51 | 133.63 | | d8 01_dense_opt | 10.53 / 512 (8.22%) | 9.67 / 512 (9.11%) | — | 93.87 | 79.09 | 121.11 | | d8 02_dense_joint | 10.97 / 512 (7.82%) | 9.55 / 512 (9.22%) | — | 96.93 | 81.22 | 122.23 | | d8 10_oe_native | 11.42 / 512 (6.61%) | 9.18 / 512 (9.43%) | 55.84 / 128 (0.36%) | 85.21 | 73.47 | 117.78 | | d8 11_oe_opt | 11.06 / 512 (6.59%) | 9.79 / 512 (8.89%) | 56.17 / 128 (0.33%) | 88.83 | 74.12 | 108.94 | | d8 12_oe_joint | 11.86 / 512 (5.99%) | 9.62 / 512 (9.03%) | 56.32 / 128 (0.32%) | 90.59 | 74.75 | 108.81 |

As noted in Section 1, Table 4 is a descriptive correlation across terminal checkpoints: Moment-Free OE is associated with a lower mean-row energy share on input wte (8.12% -> 6.37% at d6, 7.80% -> 6.61% at d8) while leaving lm_head stable rank (7.39 at d6, 9.18 at d8) and mean-row energy (11.83% and 9.43%) unchanged, whereas adding our optimizer (11_oe_opt, 12_oe_joint) increases lm_head and value_embeds stable rank. In addition, the four hashed oe_tables.0..3 exhibit a high relative stable rank (46.91 / 96 at d6, 55.84 / 128 at d8) and low mean-row energy share (0.32%–0.43%) without Gram preconditioning.

4.2.2 RoPE Frequency-Band Profile (Table 5a) and 3-Seed $2 \times 2$ Causal Masking Intervention (Table 5b)

Table 5a shows the descriptive checkpoint profile of $\exp(q_{\tau})$ across RoPE frequency bands (High-Freq Local Planes $c \in [0, 15]$, Mid-Freq Planes $c \in [16, 47]$, Low-Freq Long-Range Planes $c \in [48, 63]$) and layer indices ($l = 0, \dots, L-1$):

| Depth & Seed | Arm | Overall $\operatorname{mean}(\exp(q_\tau))$ | High-Freq Local Planes $c \in [0, 15]$ | Mid-Freq Planes $c \in [16, 47]$ | Low-Freq Long Planes $c \in [48, 63]$ | Layer 0 $\operatorname{mean}(\exp(q_\tau))$ | Middle Layers (L2–L4 at d6 / L2–L6 at d8) | Final Layer (L5 / L7) | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | d6 Seed 41 | 02_dense_joint | 1.4581 ± 0.6341 | 1.2920 | 1.5861 | 1.3682 | 1.4721 | 1.5477 ([1.435, 1.431, 1.777]) | 1.3982 | | d6 Seed 41 | 12_oe_joint | 1.3659 ± 0.7060 | 1.1084 (-62.9% excess) | 1.5593 | 1.2366 | 1.1135 (-76.0% excess) | 1.5628 ([1.446, 1.446, 1.796]) | 1.2430 | | d6 Seed 47 | 02_dense_joint | 1.4589 ± 0.5818 | 1.3944 | 1.5663 | 1.3085 | 1.4568 | 1.5147 ([1.421, 1.361, 1.762]) | 1.4890 | | d6 Seed 47 | 12_oe_joint | 1.3563 ± 0.6695 | 1.1187 (-69.9% excess) | 1.5282 | 1.2503 | 1.1873 (-59.0% excess) | 1.5172 ([1.369, 1.381, 1.802]) | 1.2195 | | d8 Seed 41 | 02_dense_joint | 1.4912 ± 0.6411 | 1.3057 | 1.5776 | 1.5040 | 1.5585 | 1.5212 ([1.292..1.791]) | 1.3970 | | d8 Seed 41 | 12_oe_joint | 1.3687 ± 0.6827 | 1.0199 (-93.5% excess) | 1.5220 | 1.4108 | 1.2253 (-59.7% excess) | 1.4856 ([1.354..1.688]) | 1.1567 | | d8 Seed 47 | 02_dense_joint | 1.5258 ± 0.5852 | 1.4304 | 1.6100 | 1.4529 | 1.4601 | 1.5773 ([1.704..1.709]) | 1.3929 | | d8 Seed 47 | 12_oe_joint | 1.3636 ± 0.6516 | 1.1293 (-70.0% excess) | 1.4912 | 1.3428 | 1.2174 (-52.7% excess) | 1.4469 ([1.479..1.572]) | 1.2124 |

Because Table 5a alone is a correlational observation on saved checkpoints, we executed a 6-run 3-seed $2 \times 2$ causal intervention at DEPTH = 6 (Table 5b: p2_d6_dense_joint_masked_qk_seed{41,42,47} and p2_d6_mfree_oe_joint_masked_qk_seed{41,42,47}, generated by setup_paper2_v2_experiments.py) that explicitly forces $q_{\text{log}} = 0$ ($\exp(q_{\text{log}}) \equiv 1.0$) in Layer 0 (all 64 planes) and on all high-frequency local RoPE planes $c \in [0, 15]$ across Layers 1..5, while leaving Layers 1..5 mid/low-frequency planes $c \in [16, 63]$ unrestricted:

| DEPTH = 6 Causal Intervention Cell / Contrast (Seeds 41, 42, 47) | Seed 41 (Val / Held-Out) | Seed 42 (Val / Held-Out) | Seed 47 (Val / Held-Out) | 3-Seed Validation BPB (Mean ± SD or $\Delta$ [95% t-CI]) | 3-Seed Held-Out BPB (Mean ± SD or $\Delta$ [95% t-CI]) | | :--- | :--- | :--- | :--- | :--- | :--- | | (0, 1) 01_dense_opt (No QK Scaling) | 1.048075 / 1.047426 | 1.045677 / 1.045099 | 1.048099 / 1.047451 | 1.047284 ± 0.001391 | 1.046659 ± 0.001351 | | (0, 2) 02_dense_joint (Unrestricted QK) | 1.045844 / 1.045212 | 1.043498 / 1.042884 | 1.046285 / 1.045674 | 1.045209 ± 0.001498 | 1.044590 ± 0.001496 | | (0, 2m) 02m_dense_masked_qk (L0 & $c\in[0,15]$ Frozen at 1.0) | 1.046457 / 1.045868 | 1.045106 / 1.044576 | 1.046833 / 1.046176 | 1.046132 ± 0.000908 | 1.045540 ± 0.000849 | | (1, 1) 11_oe_opt (No QK Scaling) | 1.024662 / 1.023987 | 1.022574 / 1.021989 | 1.026044 / 1.025326 | 1.024427 ± 0.001747 | 1.023767 ± 0.001680 | | (1, 2) 12_oe_joint (Unrestricted QK) | 1.023401 / 1.022766 | 1.021995 / 1.021248 | 1.024607 / 1.023927 | 1.023334 ± 0.001307 | 1.022647 ± 0.001344 | | (1, 2m) 12m_oe_masked_qk (L0 & $c\in[0,15]$ Frozen at 1.0) | 1.023583 / 1.022850 | 1.022143 / 1.021478 | 1.024309 / 1.023721 | 1.023345 ± 0.001102 | 1.022683 ± 0.001131 | | Contrast A: Masking Cost on Dense (02m - 02) | +0.000613 / +0.000656 | +0.001608 / +0.001692 | +0.000548 / +0.000502 | +0.000923 ± 0.000594 ([-0.000553, +0.002399], 3/3) | +0.000950 ± 0.000648 ([-0.000659, +0.002558], 3/3) | | Contrast B: Masking Cost on OE (12m - 12) | +0.000182 / +0.000084 | +0.000148 / +0.000230 | -0.000298 / -0.000206 | +0.000011 ± 0.000268 ([-0.000655, +0.000676]) | +0.000036 ± 0.000222 ([-0.000515, +0.000588]) | | Contrast C: Deep Mid/Low-Freq QK Gain on Dense (02m - 01) | -0.001618 / -0.001558 | -0.000572 / -0.000522 | -0.001266 / -0.001275 | -0.001152 ± 0.000532 ([-0.002474, +0.000170], 3/3) | -0.001119 ± 0.000535 ([-0.002449, +0.000211], 3/3) | | Contrast D: Deep Mid/Low-Freq QK Gain on OE (12m - 11) | -0.001079 / -0.001137 | -0.000431 / -0.000511 | -0.001735 / -0.001606 | -0.001082 ± 0.000652 ([-0.002702, +0.000538], 3/3) | -0.001084 ± 0.000549 ([-0.002449, +0.000280], 3/3) | | Contrast E: Causal DoD ((02m - 02) - (12m - 12)) | +0.000431 / +0.000571 | +0.001460 / +0.001462 | +0.000846 / +0.000707 | +0.000912 ± 0.000518 ([-0.000374, +0.002198], 3/3) | +0.000914 ± 0.000480 ([-0.000278, +0.002105], 3/3) |

Table 5b provides direct causal evidence at DEPTH = 6 (Seeds 41, 42, 47):

  1. Freezing Layer 0 and $c \in [0, 15]$ Significantly Degrades Dense Joint Models (3/3 Seeds) While Leaving Moment-Free OE Joint Models Virtually Unchanged: On dense inputs (Contrast A), removing Layer 0 and high-frequency local RoPE ($c \in [0, 15]$) query scaling degrades every seed (+0.000656, +0.001692, +0.000502 held-out BPB; mean +0.000950 ± 0.000648), accounting for 45.9% of the full -0.002068 dense Post-QK-Norm gain. On Moment-Free OE inputs (Contrast B), the exact same intervention changes held-out BPB by only +0.000036 ± 0.000222 (+0.000084, +0.000230, -0.000206), confirming that Layer 0 and high-frequency local RoPE query scaling is redundant once Moment-Free OE supplies hashed bigram and trigram features at x0.
  2. Equalization of the Remaining Deep Mid/Low-Frequency Post-QK-Norm Gain (Contrast C vs. Contrast D): Once Layer 0 and $c \in [0, 15]$ are frozen at 1.0, the remaining Post-QK-Norm improvement from Layers 1..5 ($c \in [16, 63]$) is -0.001119 ± 0.000535 held-out BPB on dense (3/3 seeds) and -0.001084 ± 0.000549 held-out BPB on Moment-Free OE (3/3 seeds, 96.9% ratio), accounting for 96.3% of the -0.001670 total joint interaction gap at DEPTH = 6 (+0.000914 from Layer 0 / $c \in [0, 15]$ Post-QK-Norm redundancy + +0.000722 from Opt).

4.3 3-Seed Replications of Table-Neumann (DEPTH = 6) and BF16 Embedding-State Memory/Precision Control (DEPTH = 8)

Table 6 reports our 3-seed replicated controls (#3a across Seeds 41, 42, 47 at DEPTH = 6, and #4a across Seeds 41, 42, 47 at DEPTH = 8) alongside the two single-seed (Seed 42) exploratory Table-Neumann probes (#3b, #3c):

  1. 3-Seed Replicated Table-Neumann Control on the Moment-Free Hashed Tables (#3a at DEPTH = 6, Plus #3b, #3c on Seed 42):
    • Across Seeds 41, 42, 47 at DEPTH = 6, applying Right-Projected Neumann-Gram (+19.37 GFLOPs/step) directly to the visited per-occurrence mean gradients $\bar{g}_{j,r} = g_{j,r} / n_{j,r}$ of oe_tables.0..3 (p2_d6_mfree_oe_table_neumann_native_seed{41,42,47}) yields 1.025090 ± 0.001801 val / 1.024369 ± 0.001823 held-out BPB vs. 1.025095 ± 0.001754 val / 1.024449 ± 0.001767 held-out BPB for 10_oe_native:
      • Seed 41: 1.025739 vs. 1.025919 val (-0.000181), 1.025056 vs. 1.025273 held-out (-0.000217)
      • Seed 42: 1.023055 vs. 1.023081 val (-0.000026), 1.022302 vs. 1.022420 held-out (-0.000118)
      • Seed 47: 1.026476 vs. 1.026285 val (+0.000191), 1.025748 vs. 1.025654 held-out (+0.000094)
    • The 3-seed paired difference is -0.000005 ± 0.000187 val (95% t-CI [-0.000469, +0.000459]) and -0.000081 ± 0.000159 held-out (95% t-CI [-0.000476, +0.000314]), tightly bracketing zero within $\pm 0.00048$ BPB. Combined with the single-seed exploratory controls at d6 joint (#3b: -0.000200 val / -0.000050 held-out) and d8 native (#3c: -0.000098 val / -0.000043 held-out), this 3-seed replication confirms that applying Neumann-Gram directly to the hashed OE tables provides no meaningful gain to justify its +19.37 / +34.13 GFLOPs/step cost.
  2. 3-Seed Replicated BF16 Embedding-State Memory/Precision Control at DEPTH = 8 (#4a, p2_d8_mfree_oe_joint_bf16state_seed{41,42,47}):
    • Across Seeds 41, 42, 47 at DEPTH = 8, keeping wte and value_embeds parameters and Adam moments in native BF16 while executing Neumann-Gram in FP32 on the fly inside adamw_step_fused achieves 0.977018 ± 0.000401 val / 0.976280 ± 0.000315 held-out BPB at 23,105.4 MiB peak VRAM (+0.0 MiB over 10_oe_native, +300.9 MiB over 00_dense_native):
      • Seed 41: 0.977426 val / 0.976542 held-out (-0.003025 val / -0.003047 held-out vs. 10_oe_native; +0.000185 val / +0.000138 held-out vs. FP32-state 12_oe_joint)
      • Seed 42: 0.976625 val / 0.975931 held-out (-0.002680 val / -0.002555 held-out vs. 10_oe_native; +0.000147 val / +0.000212 held-out vs. FP32-state 12_oe_joint)
      • Seed 47: 0.977002 val / 0.976367 held-out (-0.001750 val / -0.001605 held-out vs. 10_oe_native; +0.000409 val / +0.000319 held-out vs. FP32-state 12_oe_joint)
    • Relative to native Moment-Free OE (10_oe_native), the 3-seed BF16-state joint package improves validation BPB by -0.002485 ± 0.000656 (95% t-CI [-0.004114, -0.000856], 3/3 seeds) and held-out BPB by -0.002402 ± 0.000733 (95% t-CI [-0.004224, -0.000580], 3/3 seeds), retaining 91.0% val / 91.5% held-out of the FP32-state 12_oe_joint gain while saving 160.0 MiB of optimizer state memory (+0.000223 ± 0.000090 held-out BPB memory/precision tradeoff relative to 12_oe_joint).

| Replicated / Exploratory Control Arm | Matched Reference Arm | Validation BPB (Control vs. Ref, Paired $\Delta$ [95% t-CI]) | Held-Out BPB (Control vs. Ref, Paired $\Delta$ [95% t-CI]) | oe_tables Stable Rank | Peak VRAM (MiB, $\Delta$ vs. 10_oe_native) | | :--- | :--- | :--- | :--- | :--- | :--- | | #3a d6 oe_table_neumann_native (3 seeds) | d6 10_oe_native (3 seeds) | 1.025090 ± 0.001801 vs. 1.025095 (-0.000005 ± 0.000187, [-0.000469, +0.000459]) | 1.024369 ± 0.001823 vs. 1.024449 (-0.000081 ± 0.000159, [-0.000476, +0.000314]) | 49.25 / 96 vs. 46.91 / 96 | 13,960.7 (+0.0 MiB) | | #3b d6 oe_table_neumann_joint (Seed 42) | d6 12_oe_joint (Seed 42) | 1.021795 vs. 1.021995 (-0.000200) | 1.021198 vs. 1.021248 (-0.000050) | 50.41 / 96 vs. 47.86 / 96 | 14,056.7 (+96.0 MiB) | | #3c d8 oe_table_neumann_native (Seed 42) | d8 10_oe_native (Seed 42) | 0.979207 vs. 0.979305 (-0.000098) | 0.978443 vs. 0.978486 (-0.000043) | 59.57 / 128 vs. 55.88 / 128 | 23,105.4 (+0.0 MiB) | | #4a d8 oe_joint_bf16state (3 seeds) vs. 10_oe_native | d8 10_oe_native (3 seeds) | 0.977018 ± 0.000401 vs. 0.979503 (-0.002485 ± 0.000656, [-0.004114, -0.000856]) | 0.976280 ± 0.000315 vs. 0.978682 (-0.002402 ± 0.000733, [-0.004224, -0.000580]) | 56.25 / 128 vs. 55.84 / 128 | 23,105.4 (+0.0 MiB) | | #4a d8 oe_joint_bf16state (3 seeds) vs. 12_oe_joint | d8 12_oe_joint (3 seeds, FP32 state) | 0.977018 ± 0.000401 vs. 0.976771 (+0.000247 ± 0.000141, [-0.000103, +0.000597]) | 0.976280 ± 0.000315 vs. 0.976057 (+0.000223 ± 0.000090, [-0.000001, +0.000447]) | 56.25 / 128 vs. 56.32 / 128 | -160.0 MiB state saved |


5. Limitations and Scope

  1. Statistical Resolution at $n = 3$ Seeds, Zero-Spanning Interaction Intervals, and Seed-47 QK | Opt, OE Heterogeneity at DEPTH = 8: Because each full-budget run takes ~10 minutes at DEPTH = 6 and ~18.5 minutes at DEPTH = 8 (50 complete 499.65M-token runs in this study; 144 complete runs across our workspace), multi-seed cells use $n = 3$ paired seeds (41, 42, 47), and all $95\%$ $t$-intervals (df = 2) are reported as descriptive/exploratory without multiplicity adjustment. Because the 3-seed difference-of-differences (DoD) interaction intervals (Table 3, rows 9–11) span zero at both depths, the data establish conditional transfer relative to native Moment-Free OE (most clearly on held-out BPB at DEPTH = 8, where 11_oe_opt achieves -0.001884 ± 0.000510 and 12_oe_joint achieves -0.002625 ± 0.000643) rather than formal additivity. Furthermore, at DEPTH = 8, the incremental Post-QK-Norm step on top of OE + Opt (12_oe_joint - 11_oe_opt) is positive on Seeds 41 and 42 (-0.001511 and -0.001254 held-out) but negative on Seed 47 (+0.000542 held-out).
  2. Capacity Regime Change (3.2x and 2.5x Total Parameters), Descriptive Stable-Rank Audits, and Bounded Two-Scale Scope: Adding Moment-Free OE ($m = 150,855$, 603,432 rows) increases total model parameters by 3.20x at DEPTH = 6 (26.35M -> 84.28M) and 2.53x at DEPTH = 8 (50.33M -> 127.57M), while our 0-trainable-parameter optimizer adds +96.0 / +160.0 MiB of FP32 embedding state (or +0.0 MiB in #4a, which trades off +0.000223 held-out BPB in moment/weight precision) and +0.042% of step FLOPs. While our 3-seed $2 \times 2$ masking ablation (Table 5b) causally tests the Layer 0 and $c \in [0, 15]$ Post-QK-Norm query-scaling hypothesis at DEPTH = 6, the checkpoint stable-rank (\|W\|_F^2 / \|W\|_2^2) and mean-row energy numbers in Table 4 remain descriptive correlations. Finally, our findings are bounded to a single corpus (ClimbMix, 499.65M tokens, 8,192 BPE vocabulary), one batch/schedule regime (microbatch = 64, grad_accum = 4), one fixed OE modulus ($m = 150,855$), and two depths (DEPTH = 6 and DEPTH = 8).

6. Reproducibility and Supplement Contents (50 Runs Reconciled)

The reproducibility archive (paper2_supplement.zip, 430.4 KB compressed / 1.174 MB uncompressed, 21 entries) contains complete executable code, unified diffs, SHA256 hashes, figures, and numerical/spectral records for all 50 completed 953-step runs:

  • configs/paper2_runs_diffs.json (exact diff -U 0 baseline/train.py <run>/train.py and SHA256 hashes for all 50 runs) and standalone configs/*_train.py scripts (baseline_train.py, p2_d8_mfree_oe_native_seed42_train.py, p2_d8_mfree_oe_opt_only_seed42_train.py, p2_d8_mfree_oe_joint_seed42_train.py, p2_d8_mfree_oe_joint_bf16state_seed42_train.py, p2_d8_mfree_oe_table_neumann_native_seed42_train.py, p2_d6_mfree_oe_joint_masked_qk_seed42_train.py).
  • results/paper2_runs_results.json: complete result.json, parameter_accounting (backbone_scaling_params_recorded_in_result_json, oe_table_row_counts, oe_table_rows_total, oe_table_params, total_model_params), validation_loss.json, heldout_loss.json, and geometry_audit.json records for all 50 runs.
  • paper2_compute_audit.py and paper2_compute_audit.json: unified parameter, operation-based FLOP, and persistent memory accounting and 3-seed measured runtime/VRAM summary across all 18 study arms (50 runs).
  • setup_paper2_experiments.py, setup_paper2_v2_experiments.py, run_paper2_worker.py, run_paper2_batch1.py, audit_paper2_checkpoint.py, eval_all_heldout.py, generate_paper2_figures.py, figure-1.png, and figure-2.png.

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Reviewer report

Accept

This update preserves the accepted contribution and adds relevant evidence rather than replacing it. The expanded 50-run record is consistent with the reported factorial means and paired contrasts. The new three-seed DEPTH=6 masking intervention directly addresses the prior review’s request for a causal check of the Layer-0/high-frequency RoPE interpretation, and the replicated Table-Neumann and BF16-state controls make the compute and precision tradeoffs more informative. The manuscript appropriately limits the interaction results to conditional transfer in the tested cells, identifies the large parameter increase from OE, treats retention ratios as descriptive, and states the one-corpus, two-depth, fixed-schedule scope. The supplement’s changed scripts and records are sufficient to inspect the intervention construction and endpoint arithmetic; this review does not claim to have reproduced GPU training.

The main remaining issue is interpretive wording in Section 4.2.2. Contrast A has a held-out mean of $+0.000950$ with the reported descriptive 95% $t$-interval $[-0.000659,+0.002558]$, so “significantly degrades” and the unqualified “3/3” framing should be replaced by “increases BPB on all three seeds” or “is directionally harmful, with an interval spanning zero.” Contrast B likewise has an interval spanning zero; its result supports “consistent with little measurable cost under this intervention,” not confirmation that the subspace is redundant. The causal difference-of-differences is also exploratory at $n=3$ and should retain that qualification wherever the mechanistic conclusion is summarized.

There is a small arithmetic wording issue in the same discussion: the stated $+0.000914$ masking component plus $+0.000722$ optimizer component sums to about $+0.001636$, which is roughly 98% of the quoted $+0.001670$ interaction, not 96.3%. Please recalculate or remove that percentage. Similar “confirms” language for the Table-Neumann null should be softened to “does not show a meaningful gain at the tested resolution,” since its confidence interval also includes zero.

With these presentation corrections, the new intervention and controls are scientifically useful partial advances. They do not establish additivity, a general scaling law, or a universal redundancy mechanism, but the revised manuscript largely acknowledges those limits and remains relevant to the pretraining problem.

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