Dimension is the most foundational concept across mathematics, physics and engineering, yet mainstream academia only provides coordinate-based descriptive definitions (1D line, 2D surface, 3D volume, 4D spacetime) without answering the origin, intrinsic structure and convergence rules of dimensions themselves. This paper first defines the effective discussion boundary of dimensional research: dimensions are meaningless in the Universal Universe without unfolded structures, remain unconsolidated transitional states in the Hun-Dong chaotic generation process, and only obtain definite structural meaning within the topological cosmos from 0-Interface generation to the number-theoretic projection layer. This research divides mathematical systems into three mutually independent categories: Ontological Mathematics (intrinsic topological constraint laws of the cosmos, parameter-free), Abstract Mathematics (human-constructed formal self-consistent systems, arbitrary dimensional definition allowed), Instrumental Mathematics (human-developed computational tools, effective only on the 3D projection layer). Mainstream scientific confusion over dimensions arises from conflating abstract/instrumental coordinate dimensions with ontological structural dimensions. The paper proposes original ontological structural definitions for all dimensions: 1D refers to the establishment of directional logic; 2D denotes the unfolding range of topological extension; 3D represents the accumulation state of structural entities; 4D is the unified flowing whole integrating 1/2/3D (flow variables), with 3D volume merely its solidified projection state. 5D is the local steady-state convergence unit satisfying 5=1+4; dimensions 6–10 are unstable rheological transitional structures without independent steady-state closure; 11D is the global topological steady-state convergence blueprint derived from coupling three 5D local structures after eliminating redundant 4D fields. Three stratified starting points of cosmic logic are distinguished: Logical Ontology Itself (ultimate foundational source), 0-Interface (structural unfolding origin of dimensions), and the manifestation of unit 1 (human perceptual starting point). The layers of the cosmos, logical hierarchy and dimensional stratification are isomorphic expressions of the same topological structure. This paper finalizes the full panoramic architecture of the PFUSRC framework, sorts out targeted reading paths for researchers of different disciplines, and serves as the concluding systematic overview of the complete PFUSRC theoretical series.
Zhenmin Wang (Sun,) studied this question.