Была неизвестна точная оценка, при каком минимальном A можно из прямоугольника 1 на A склеить лист Мёбиуса и изометрично (не растягивая и не сжимая) вложить (то есть без углов) в трёхмерное пространство (см. и книжку Математический дивертисмент). Я много где студентам и школьникам про это рассказывал, рекламировал.
А недавно Ричард Шварц доказал, что оценка A>√3 оптимальная (видео).
Была неизвестна точная оценка, при каком минимальном A можно из прямоугольника 1 на A склеить лист Мёбиуса и изометрично (не растягивая и не сжимая) вложить (то есть без углов) в трёхмерное пространство (см. и книжку Математический дивертисмент). Я много где студентам и школьникам про это рассказывал, рекламировал.
А недавно Ричард Шварц доказал, что оценка A>√3 оптимальная (видео).
Channels are not fully encrypted, end-to-end. All communications on a Telegram channel can be seen by anyone on the channel and are also visible to Telegram. Telegram may be asked by a government to hand over the communications from a channel. Telegram has a history of standing up to Russian government requests for data, but how comfortable you are relying on that history to predict future behavior is up to you. Because Telegram has this data, it may also be stolen by hackers or leaked by an internal employee. At its heart, Telegram is little more than a messaging app like WhatsApp or Signal. But it also offers open channels that enable a single user, or a group of users, to communicate with large numbers in a method similar to a Twitter account. This has proven to be both a blessing and a curse for Telegram and its users, since these channels can be used for both good and ill. Right now, as Wired reports, the app is a key way for Ukrainians to receive updates from the government during the invasion. Some privacy experts say Telegram is not secure enough The regulator said it had received information that messages containing stock tips and other investment advice with respect to selected listed companies are being widely circulated through websites and social media platforms such as Telegram, Facebook, WhatsApp and Instagram. "We as Ukrainians believe that the truth is on our side, whether it's truth that you're proclaiming about the war and everything else, why would you want to hide it?," he said.
from sg
