The U.S. says it has accepted an invitation to attend China's top annual security forum in late October, the latest sign of potentially warming ties between the two countries' militaries. Washington has been eager to revive military-to-military communications with China, its main strategic rival, and three sources familiar with the matter said Beijing had invited Defense Secretary Lloyd Austin to attend its Xiangshan forum, scheduled for Oct. 29 – 31. The United States, however, won't send Austi