Space-Time Freedom Degree and Space-Time Geometry Type
[1]
Wu Xinzhong, School of History and Culture of Science, Shanghai Jiaotong University, Shanghai, China.
In this paper we study how 4d space-time geometry changes with its freedom degree. Space-time freedom degrees represent the number of variable constraints. When a constraint is fixed, its corresponding freedom degree will disappear so that space-time geometry has some symmetries caused by this fixed constraint, and becomes a new type in general space-time. Fixed constraints represent some kinds of space-time symmetry which relate with physics laws expressed by empirical facts. We find that gravitational gauge theories have larger space-time freedom degree than general relativity, and general relativity can be introduced to gauge conditions such as the harmonic coordinates, eliminates its space-time freedom degree and become a new gravity theory in flat space-time which is like Minkowski space-time in special relativity. Various equivalence theories of general relativity are also accompanied by the change of freedom degree of space–time.
Space-Time Freedom Degree, Gravity Theory, Space-Time Type
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