diff options
Diffstat (limited to 'EXTENDED_ABSTRACT.md')
| -rw-r--r-- | EXTENDED_ABSTRACT.md | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/EXTENDED_ABSTRACT.md b/EXTENDED_ABSTRACT.md new file mode 100644 index 0000000..1a75b8c --- /dev/null +++ b/EXTENDED_ABSTRACT.md @@ -0,0 +1,156 @@ +# World Alignment: recovering cross-modal correspondence from corpora that share no example + +## The correspondence can be searched rather than bought + +Every multimodal system in use buys its cross-modal correspondence with +paired data. CLIP pays in hundreds of millions of image-text pairs; a +frozen-backbone connector pays less but still pays; unsupervised +captioning pays covertly, through a supervised detector's label space. +We ask what happens when nothing is paid: two corpora, one of images and +one of text, collected separately, overlapping in the world they describe +but sharing no example and carrying no link between them. + +The premise is that a correspondence need not be learned if it is already +determined. Two sufficient descriptions of one world must satisfy the +same relational structure, and that structure is a constraint on the +unknown correspondence — enough of it, and the correspondence becomes +identifiable. The method that follows treats the cross-modal bridge as a +variable to be solved for under that constraint, never as weights to be +fitted, which is what separates it from both contrastive pairing and any +cross-modal predictive objective. + +## States are sets, relations are fields, and the bridge is a coupling + +Four commitments define the method, each forced by a measured failure of +its alternative. + +**A scene state is a set of part states, not a pooled vector.** Pooled +embeddings of independently trained encoders share a cross-modal +subspace of roughly sixteen population directions — projecting onto the +top sixteen raises relational agreement from 0.306 to 0.367, and +whitening the full spectrum collapses it to 0.03. Sixteen coarse +dimensions cannot separate five hundred instances, so no energy over +pooled states passes a local-ordering test, and none did across eighteen +conditions. + +**Relations are computed within each modality and compared as fields.** +Writing a scene as a set of part states, its relation to another scene is +a moment kernel of the two sets; the field of all such relations is the +object the two modalities must agree on. Fields are invariant to how each +side labels its own features, so no shared vocabulary is presupposed — +a fact we established by accident, when an oracle class alignment and a +frequency-rank alignment produced bit-identical fields while agreeing on +none of twenty-three classes. + +**The energy is a functional of one matrix.** With `M` the elementwise +product of the permuted text field and the visual field, the pairwise +term is a constant less `2·sum(M)` and the all-triple term a constant +less `2·tr(M³)/6`, because traces of powers survive simultaneous +row-column permutation. One batched matrix product scores hundreds of +candidate couplings over every triple, and the same identity opens +`tr(M^k)` for any order. + +**Solving is spectral first, then local.** A spectral solver reads the +coarse correspondence out of the eigenstructure in polynomial time and +never becomes trapped, but rounds badly; exact steepest descent on the +closed-form energy rounds well but cannot find the basin from a random +start. Composed, they recover; separately, they do not — 53.5% and 7.0% +alone against 95.3% together. + +## The gate decides before the search runs + +A candidate energy is admitted only if the true configuration is the +deepest state a strong searcher reaches. This sounds procedural and is +the single most productive rule in the project, because the intuitive +substitutes are wrong in a specific way: **descent retention measures the +search operator, not the energy.** Sampled-proposal descent kept the +truth for every candidate energy tested at five hundred scenes; long +tempering on the same energies reached 10% below it. Three times a limit +looked intrinsic and proved to belong to the solver — retention, a +third-order energy that appeared to pass, and a value-alignment ceiling +of six correct entries in ten that combining two signals lifted to ten. +Each was settled by computing the bound rather than inferring it. + +The gate yields a cheap predictor. Recovery tracks a single measurable +quantity, the correlation between the two relation fields at the true +pairing, and the phase boundary sits where correlated-matching theory +puts it: at five hundred scenes the information-theoretic threshold is +near 0.29 and the polynomial-algorithm threshold near 0.9. Nothing we +built worked below 0.9, and recovery appeared as soon as fields crossed +it. Any new representation can therefore be priced in minutes, before a +single search is run. + +## A closed world settles the mechanism + +A procedurally generated world makes representational sufficiency a +construction rather than a hope: scenes are sets of object groups with +spatial relations, captions state exactly the discrete state in a +43-word vocabulary, and renders resample layout so that what views share +is precisely the world state. Vision-only and text-only splits are +disjoint scenes. + +Three unimodal operations — appearance grouping, distance-transform +watershed for touching objects, and one-dimensional clustering of radial +extent for size classes — take the field correlation from 0.570 to +0.928, and blind recovery from 5.1% to **95.3% exact scene +identification** at 256 scenes against 0.39% chance, replicated at 96.1% +and 96.1% over two further hidden shuffles and 84.7% at 600 scenes. + +Recovery would be a curiosity if it could not be spent. Treated as +pseudo-pair supervision for a ridge map and applied to 200 held-out +scenes that took no part in matching, it reaches **93.0% exact +retrieval** against 0.5% chance, with colour-set F1 of 0.989 and count +multisets exact 97.5% of the time. The random-pair control lands exactly +on chance and the shuffled-image control drops colour F1 to 0.295, so +the output is conditioned on the image and extrapolates beyond the +matched population. Matching is a bootstrap for the map, not the +deployment mechanism, which is why population size binds far less than +the recovery curve alone suggests. + +Cross-modal value correspondence is derived, not declared. Text factor +families come from distributional structure, vision classes from +clustering raw appearance, and the two are paired by marginal frequency +rank and colour-by-shape joint structure — read from 6,000 text-only and +6,000 vision-only scenes with no shared instance. The derivation is +exactly right on ten of ten colour terms, and survives a world where +captions name only half the objects present and the pixel and text +frequency rankings diverge in the tail. + +## Natural data is not there yet, and the deficit is located + +Ported to Visual Genome under the same recipe — DINOv2 patch features, +spectral segmentation, distributional word statistics — the field +correlation reaches 0.656, against the 0.9 recovery needs. No recovery +run is warranted, and the trajectory that got there is more informative +than the number. + +Discretisation cost more than half the signal: hard class codes give +0.166 where continuous states give 0.489, because fields need only +scene similarity and quantising states first is attrition the synthetic +world hid by being discrete already. Segmentation is not the wall on +photographs — annotated boxes buy 0.061 over unsupervised spectral +segmentation, the inverse of the closed world where segmentation was the +entire gap, since flat untextured scenes are adversarial for object +discovery in a way photographs are not. Content projection is the +largest lever at 0.489 to 0.656. General-purpose frozen encoders +underperform corpus-fitted statistics, 0.19 against 0.656, so in-context +features beat isolated crops and corpus-specific vectors beat a language +model's pooled states. + +## What is not shown + +The closed-world result uses object states built by hand; no +self-supervised recipe we tested — orbit contrastive, masked pixel +reconstruction, their hybrid, masked feature prediction, or slot +attention at two resolutions — produced their equivalent, each failing +by a distinct measured mechanism. Natural data sits 0.24 below the +recovery threshold. No frozen language model has been driven end to end +on natural data by a recovered correspondence, though a paired control +establishes that the interface works once the correspondence is right. + +The untried lever is the one the closed world identified as a protocol +requirement: two-sided multi-view observation. Visual Genome offers one +photograph per scene, so orbits must come from augmentation or from +corpora that carry them natively. Whether that closes 0.656 to 0.9 is +the next measurement, and the gate will answer it before any search is +run. |
