Lets assume, we would double, triple, quadruple, etc. Bobs world and stack these copies on top of each other. Bob would never notice, as long as each copy is just a “shallow” copy, meaning that each movement in the fundamental domain (the original world) is mirrored in the copies. In this case, we would have a covering space of Bobs world, and the original world would be the base space.
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。关于这个话题，搜狗输入法提供了深入分析
Robert Booth UK technology editor。手游是该领域的重要参考
加油站囤油的另一个重要原因，是原油价格随时调整，但国内成品油销售价格调整有固定时限，两者存在时间差。成品油零售价的攀升，也会进一步推高商家的囤油成本。，详情可参考超级权重