A filled torus (a doughnut) is a 3-manifold homeomorphic to \(S^1 \times D^2\), where \(D^2\) is the 2-dimensional disk. There exists a deformation retract from the doughnut to a circle, so the fundamental group of the doughnut is \(\pi_1(S^1 \times D^2) \cong \mathbb{Z}\).
The bank’s most dramatic scenario is a three-month, full disruption to oil and liquefied natural gas flows. This would likely see oil prices spiking to records through the second quarter, the bank’s analysts wrote in a note.
。新收录的资料是该领域的重要参考
assert verify([2] + [3],
Европеец описал впечатления от дворца в России фразой «рот открылся и не закрывался»17:34
An accountant won a big jackpot on Kalshi by betting against DOGE