Asian stock markets were mostly higher Tuesday after Wall Street rose on a flurry of corporate deals and China's economic activity improved.Shanghai, Hong Kong and Seoul gained, while Tokyo retreated.Wall Street's S&P 500 index closed 1.3% higher, driven by gains for technology, health care and finance stocks after chipmaker Nvidia and other companies announced acquisitions and drugmaker AstraZeneca said clinical trials of its coronavirus vaccine will resume.“Wall St.