Topology of a Straight Line and Cosmic Closure: The 4D Conical Growth Model and Theory of Logical Origin (V1.2)

Starting from the straight line—the most elementary geometric object—this paper uses topological analysis and logical deduction to prove that the ideal Euclidean straight line has no physical reality. In a bounded, connected, closed space, a straight line is topologically equivalent to a circle. In a four-dimensional conical growing space, it appears as a spiraling closed loop. From this unique and consistent path, the paper rigorously derives the four-dimensional conical structure of the universe, clarifies singularities (cosmic seeds, highly condensed photon assemblies), fragments (composite growth units), hierarchical universes, and empty space, and finally establishes the Theory of Logical Origin. The result is a fully self-contained, non-presuppositional, gap-free, logically closed cosmological system. The text maintains both accessibility and academic rigor, reaching cosmic origin from basic geometry, and establishes an innovative and complete paradigm of cosmic understanding.