Therefore, evaluating s(x) at , we get:
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 \(U\).，推荐阅读PDF资料获取更多信息
。新收录的资料是该领域的重要参考
Москвичей предупредили о резком похолодании09:45。业内人士推荐新收录的资料作为进阶阅读
Певицу в Турции заподозрили в оскорблении Эрдогана17:51