（本报记者刘新吾、李君强整理）
Definition 1 A covering space of a topological space \(X\) is a topological space \(C\) together with a continuous surjective map \(p: C \to X\) such that for every point \(x \in X\), there exists an open neighborhood \(U\) of \(x\) such that \(p^{-1}(U) \cong F \times U\) for some discrete set \(F\) (called the fiber over \(x\)), and the map \(p\) restricted to each component of \(p^{-1}(U)\) is a homeomorphism onto \(U\).
，这一点在体育直播中也有详细论述
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This is the theoretical maximum if every cell is fully programmed, real data, however is a mix. Average added mass is less (half that for random data). It’s so small that no scale on Earth could detect it, and factors like dust, temperature expansion, or even the drive’s plastic casing flexing would dwarf it. Some sources flip the convention (claiming drives get lighter), but that’s based on outdated or incorrect assumptions about ‘0’ vs. ‘1’ states. The net effect is a tiny increase when adding typical data.