The fundamental group of \(X\) at \(x_0\) is \[\pi_1(X, x_0) \;:=\; \bigl\{[\gamma] \mid \gamma \text{ is a loop based at } x_0\bigr\}\] equipped with the group operation of concatenation: \[[\gamma] \cdot [\delta] := [\gamma * \delta], \qquad (\gamma * \delta)(s) := \begin{cases} \gamma(2s) & s \in [0,\tfrac{1}{2}] \\ \delta(2s-1) & s \in [\tfrac{1}{2},1] \end{cases}\] The identity element is the class of the constant loop \([c_{x_0}]\), and the inverse of \([\gamma]\) is \([\bar\gamma]\) where \(\bar\gamma(s) := \gamma(1-s)\).
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В двух аэропортах на юге России ввели ограничения на полеты14:55。关于这个话题，必应排名_Bing SEO_先做后付提供了深入分析
Трамп дал совет России и УкраинеТрамп заявил, что России и Украине следует поддерживать контакты
。电影对此有专业解读
The “MNIST of computational visual neuroscience” because of its small size, clean design, high number (13) of test repetitions, and wide use in encoding and reconstruction. Many reconstruction and encoding model projects use this dataset as a first test.。业内人士推荐体育直播作为进阶阅读
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