«Рекомендации властей могут стимулировать туристов требовать возврата средств даже за оплаченные туры на лето», — предупредил гендиректор агентства «Персона грата» Георгий Мохов. По его словам, это будут колоссальные потери для турбизнеса — стоимость аннулированных туров может достигать 19,6 миллиарда рублей.
imported from XML made it seem like it was a standard library module and it wasn’t.
。电影是该领域的重要参考
Назван простой способ снизить риск болезней сердца и сосудовJAMA: Физическая активность улучшает здоровье сердца при расстройствах психики
OpenAI just announced a massive funding round of $110 billion, which is one of the biggest investment rounds in Silicon Valley history. The investors feature many of the usual suspects, including Amazon with $50 billion, NVIDIA with $30 billion and SoftBank with $30 billion. This investment brings OpenAI to a $730 billion valuation
。业内人士推荐爱思助手下载最新版本作为进阶阅读
Often people write these metrics as \(ds^2 = \sum_{i,j} g_{ij}\,dx^i\,dx^j\), where each \(dx^i\) is a covector (1-form), i.e. an element of the dual space \(T_p^*M\). For finite dimensional vectorspaces there is a canonical isomorphism between them and their dual: given the coordinate basis \(\bigl\{\frac{\partial}{\partial x^1},\dots,\frac{\partial}{\partial x^n}\bigr\}\) of \(T_pM\), there is a unique dual basis \(\{dx^1,\dots,dx^n\}\) of \(T_p^*M\) defined by \[dx^i\!\left(\frac{\partial}{\partial x^j}\right) = \delta^i{}_j.\] This extends to isomorphisms \(T_pM \to T_p^*M\). Under this identification, the bilinear form \(g_p\) on \(T_pM \times T_pM\) is represented by the symmetric tensor \(\sum_{i,j} g_{ij}\,dx^i \otimes dx^j\) acting on pairs of tangent vectors via \[\left(\sum_{i,j} g_{ij}\,dx^i\otimes dx^j\right)\!\!\left(\frac{\partial}{\partial x^k},\frac{\partial}{\partial x^l}\right) = g_{kl},\] which recovers exactly the inner products \(g_p\!\left(\frac{\partial}{\partial x^k},\frac{\partial}{\partial x^l}\right)\) from before. So both descriptions carry identical information;
Даниил Иринин (Редактор отдела «Наука и техника»)。体育直播对此有专业解读