MachineSex/results/recombination
Giorgio Gilestro 6f8cef1ac5 main: keep only what reproduces the manuscript; everything else lives on dev
Removed from main (all preserved on the dev branch): the arXiv build and
its sources, design documents (blueprint, results summary, review responses,
essay drafts), tasks/ and CLAUDE.md, the cover letter and reference tooling,
two unused manuscript figures, and every experiment that feeds no figure or
number in the paper: the collapse null, the sexual-vs-asexual lineage, the
NK speciation variant, the 0.5B single-seed LLM prototypes, the compose and
society experiments with their calibration and pilot runs, and their
configs, runners, tests, figure scripts and PBS jobs. Their result bundles
are moved to results/_archive/ (ignored) so the parquets stay on disk.

Also: plot_llm_speciation reads the s{seed}/ layout; the mating-breadth
plot writes under its bundle name; Makefile targets reduced to the kept
experiments; REPRODUCING.md and README point to dev for the rest.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y64o8FKP7rCuXzC48pxpMm
2026-09-13 17:07:23 +01:00
..
manifest.json recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
README.md docs: accessible figure legends (README.md) for all figures 2026-07-05 08:43:04 +01:00
recombination.pdf main: keep only what reproduces the manuscript; everything else lives on dev 2026-09-13 17:07:23 +01:00
recombination.png neural: grounding refinement + all five Layer-1.5 figures 2026-07-05 08:14:19 +01:00
resolved_config.yaml recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00

recombination — "merge, don't average" holds in real neural weights (E4 in the flesh)

Claim tested: the E4 finding — complementary specialists can rebuild the rare tail, but only if you merge them rather than average them — was proven in math. Does it survive in trained neural nets?

Setup (Layer 1.5). K_T specialist GRUs are each trained on a different slice of the rare tail (slices set by the exact shared-switch construction, so teacher count K_T, correlation ρ and retention q stay clean knobs and the construction-level union matches the closed form). The pupil then recombines the teachers' measured distributions two ways: mean (naive pooling) vs oracle-guided max-merge (per mode, keep the strongest teacher — a union-preserving merge). K = 256, n = 200, q = 0.5, swept K_T ∈ {1,2,3,5} × ρ ∈ {0, 1}, 8 repeats.

Symbols

  • K_T number of specialist teachers; ρ how correlated their retained tails are (0 = complementary, 1 = identical clones).
  • union coverage — tail covered by ≥1 teacher (the raw supply). surviving coverage — what remains after the pupil resamples.
  • mean-distill — average/pool the teachers. max-merge — keep each mode's strongest teacher (union-preserving).
  • target vs trained — coverage computed from the assigned distributions vs from the trained GRU outputs.

The four panels

  1. Supply. Union coverage vs K_T: at ρ = 0 it climbs 0.49 → 0.96 and matches the closed form U(K_T, ρ, q); at ρ = 1 (clones) it is flat. Diverse teachers supply more tail.
  2. Analytic teachers (ρ = 0). Surviving coverage vs K_T: max-merge (green) rises 0.043 → 0.087 while mean-distill (red) stays flat ~0.045 — the conservation law from E4, reproduced on the assigned distributions.
  3. Trained GRU teachers (ρ = 0). The same comparison on real trained weights: same signs — max-merge above mean-distill — but compressed and noisier (the GRU's smoothing inflates the baseline and the deep tail barely clears n = 200 resampling). The honest inductive-bias caveat.
  4. Control (ρ = 1). Identical teachers: union, max and mean are all flat — more clones buy nothing. Decorrelation is what the benefit needs.

Takeaway

"Merge, don't average" is not a mathematical artefact — in trained neural nets, a union-preserving max-merge realises the multi-teacher tail benefit while naive averaging conserves the collapse. This is load-bearing for the paper's recombination claim (and points at merging over distillation for the deferred LLM layer). Falsifier (not triggered): if mean-distill had also risen with K_T, or max never beat mean, the recombination lesson would have died in real weights.