This document is not a theory of dark matter. It does not identify the particle constituents of dark matter, does not predict cross-sections for dark matter detection experiments, and does not derive the dark matter density profile from first principles. It does not compete with or replace existing dark matter candidates — WIMPs, axions, sterile neutrinos, primordial black holes, or others. What this document offers is narrower and more modest: a set of conceptual notes proposing that the formal structure of mutual recognizability V (L2, L1), already established in SR103EN Formalization, provides a natural ontological framework for understanding what dark matter is — not what it is made of, but what kind of structural relationship it stands in with ordinary matter. The three potential points of contact are: 1. Dark matter as low mutual recognizability: dark matter is fully crystallized within Uₜotal — equally real as ordinary matter. Its electromagnetic invisibility corresponds to near-zero electromagnetic mutual recognizability: V (Ldark, Lᵤs) EM approximately 0. Its coherence process is not decomposable through electromagnetic channels. Invisibility is not a deficit of existence — it is a structural feature of the difference-series relationship between dark matter and ordinary matter. 2. Gravitational interaction as residual mutual recognizability: dark matter interacts gravitationally. Through the gravitational channel, its coherence process is partially decomposable: V (Ldark, Lᵤs) gravity > 0. Dark matter and ordinary matter share gravitational mutual recognizability while having near-zero electromagnetic mutual recognizability. This asymmetry is a structural feature of the difference-series relationship between the two types of local structure. 3. Dark matter halos as sparse electromagnetic difference-series: ordinary matter has rich electromagnetic difference-series — it can radiate, cool, and form compact structures. Dark matter has sparse or absent electromagnetic difference-series — it cannot radiate and forms only diffuse halos. The section of dark matter is determined by its interference relations with all other structures (Definition 20), but because electromagnetic interference relations are near-zero, gravitational interference dominates — resulting in diffuse extended halos. The formal tool — mutual recognizability V (L2, L1) — already exists within SR103EN Formalization. This document proposes its natural extension to channel-specific mutual recognizability as a framework for understanding the structural relationship between dark matter and ordinary matter. This document addresses Stage 1 (conceptual correspondence) only. Stage 2 onwards — formal specification of channel-specific mutual recognizability and connection to particle physics — are open problems. Prerequisite: SR103EN Formalization DOI: 10. 5281/zenodo. 20405659 Prerequisite: SR104EN Formalization DOI: 10. 5281/zenodo. 20405676 Related: Structural Hints for Quantum Gravity DOI: 10. 5281/zenodo. 20407643 Related: Structural Hints for Dark Energy DOI: 10. 5281/zenodo. 20421744
Masashi Saito (Fri,) studied this question.