Expedition Two • Front DMarch 12, 2026

Metric, Grounding, and Polysemy

Fisher Information on Context Space

Summary

This sprint completes the Prim Hom-set enumeration for the 5 primitive algebras, proving

the Yoneda-Grounding theorem: the Unique Grounding Theorem is a concrete instantiation of the Yoneda

Lemma restricted to the subcategory Prim. The Fisher information metric on context space X is shown

to be well-defined and positive semi-definite, with strict positive-definiteness proven for a toy model.

Status Summary

Proven(4)

  • Prim Hom-set enumeration (5×5 matrix)
  • Yoneda-Grounding theorem
  • Fisher metric well-defined, positive semi-definite
  • Toy model: strictly positive-definite

Framework(1)

  • Polysemy refinement (two sub-definitions)

Key Ideas

Prim Hom-Set Enumeration

Proven

The 5×5 matrix of Hom-sets between primitive algebras (Pt, Ln, An, Cv, En) has pairwise distinct row profiles.

Yoneda-Grounding Theorem

Proven

The Unique Grounding Theorem is a concrete instantiation of the Yoneda Lemma restricted to the subcategory Prim.

Fisher Information Metric

Proven

The Fisher information metric on context space X is well-defined and positive semi-definite.

Toy Model: Strictly Positive

Proven

For the toy model (X = [0,1], 3 words, rotation connection), the Fisher metric is strictly positive-definite.

Polysemy Refinement

Framework

Definition split into polysemous (genuine) vs. frame-resistant expressions.

Not Yet Addressed

  • Fisher metric for higher-dimensional X
  • Full Riemannian geometry (Christoffel symbols, geodesics)
  • Metric completion: does Fisher make X complete?

Prerequisites

  • foundations/paradigm.md
  • foundations/formal-foundations.md
  • category-of-languages
  • foundation-securing
  • probability-information

Related Open Problems

Source Document

frontier/expedition-two/metric-and-grounding.md