fundamental group of T2 topological space T2 拓扑空间的基本群
- principle of preservation of domain
- principle of realizability of goal
- principle of recursive construction
- principle of redundancy
- principle of reflection
- principle of relativity of Galilei
- principle of relativization
- principle of similarity
- principle of special relativity
- principle of stationary action
- principle of strong induction
- principle of substitution
- principle of successive division
- principle of superposition
- principle of the point of accumulation
- principle of transference
- principle of transfinite induction
- principle of trivalence
- principle of uniform boundedness
- principle of virtual displacements
- principle of virtual velocities
- principle of virtual work
- principle of weak correlation
- principle of weak induction
- Pringsheim, A.