по книге Математический дивертисмент я веду кружок по геометрии и топологии для наших студентов. Например, первое занятие было про то, что 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. Склеиваем стороны длины 1. На картинке (из книги) показано, как сложить для для любого маленького А, если допускаются углы.
по книге Математический дивертисмент я веду кружок по геометрии и топологии для наших студентов. Например, первое занятие было про то, что 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. Склеиваем стороны длины 1. На картинке (из книги) показано, как сложить для для любого маленького А, если допускаются углы.
Messages are not fully encrypted by default. That means the company could, in theory, access the content of the messages, or be forced to hand over the data at the request of a government. The news also helped traders look past another report showing decades-high inflation and shake off some of the volatility from recent sessions. The Bureau of Labor Statistics' February Consumer Price Index (CPI) this week showed another surge in prices even before Russia escalated its attacks in Ukraine. The headline CPI — soaring 7.9% over last year — underscored the sticky inflationary pressures reverberating across the U.S. economy, with everything from groceries to rents and airline fares getting more expensive for everyday consumers. Ukrainian forces have since put up a strong resistance to the Russian troops amid the war that has left hundreds of Ukrainian civilians, including children, dead, according to the United Nations. Ukrainian and international officials have accused Russia of targeting civilian populations with shelling and bombardments. Overall, extreme levels of fear in the market seems to have morphed into something more resembling concern. For example, the Cboe Volatility Index fell from its 2022 peak of 36, which it hit Monday, to around 30 on Friday, a sign of easing tensions. Meanwhile, while the price of WTI crude oil slipped from Sunday’s multiyear high $130 of barrel to $109 a pop. Markets have been expecting heavy restrictions on Russian oil, some of which the U.S. has already imposed, and that would reduce the global supply and bring about even more burdensome inflation. "The inflation fire was already hot and now with war-driven inflation added to the mix, it will grow even hotter, setting off a scramble by the world’s central banks to pull back their stimulus earlier than expected," Chris Rupkey, chief economist at FWDBONDS, wrote in an email. "A spike in inflation rates has preceded economic recessions historically and this time prices have soared to levels that once again pose a threat to growth."
from jp
