China’s highest-profile entrepreneur, Jack Ma, appeared Wednesday in an online video, ending a 2 1/2-month absence from public view that prompted speculation about the future of the e-commerce billionaire and his Alibaba Group. The Associated Press reports that in the 50-second video, Ma congratulated teachers supported by his foundation and made no mention of his disappearance or official efforts to tighten control over Alibaba and other internet companies over the past six months. The video appeared on Chinese business news and other websites. The normally voluble Ma disappeared from public view after he irked regulators by criticizing them in an Oct. 24 speech at a Shanghai conference.