The World in Brief from The Economist

OpenAI said it used an unreleased artificial intelligence model to crack one of mathematics’ trickiest problems.

The Houthis, an Iran-backed Yemeni rebel group, attacked four cities in southern Saudi Arabia, setting fire to some energy facilities and wounding at least 73 people. Also, Canada imposed retaliatory tariffs on around 700 American products, including steel, dairy and home appliances.

Canada was set to impose new tariffs on around 700 American products, including steel, dairy and home appliances.

Canada was set to impose new tariffs on around 700 American products, including steel, dairy and home appliances; Iran promised to retaliate against American attacks, warning that energy companies have assets that remain “sprawling, accessible and exposed” in the region

Ulrich Siegmund, the leader of Alternative for Germany in Saxony-Anhalt, heralded his party’s “sensational” victory in the eastern state, and said it had won a ruling mandate. Volodymyr Zelensky said he expected Ukraine’s war with Russia to continue into the winter, after meeting Donald Trump’s envoys in Kyiv.

Donald Trump’s envoys, Steve Witkoff and Jared Kushner, met Volodymyr Zelensky, Ukraine’s president, in Kyiv on Sunday—the first time they have visited his country as negotiators.

Donald Trump’s envoys, Steve Witkoff and Jared Kushner, met Volodymyr Zelensky, Ukraine’s president, in Kyiv on Sunday—the first time they have visited his country as negotiators; Election forecasts suggested the populist-right Alternative for Germany had won 44% of the vote in Saxony-Anhalt, an eastern state—more than expected

America said it struck three Iranian oil tankers after Iran launched ballistic missiles towards two of its naval ships; A guerrilla drone strike and ground assault in Colombia killed at least three soldiers and injured four, the country’s armed forces said.