East Asian powerhouses China, Japan and South Korea on Monday agreed to deepen economic relations and revitalize negotiations on a free trade agreement. In a joint declaration after a summit in Seoul, the powers emphasized their commitment to the goal of a nuclear-free Korean peninsula and political solutions for issues between South Korea and North Korea. The statement also included calls for cooperation on sustainable development, health care, science and technology, and disaster management. The countries were represented in the South Korean capital by South Korean President Yoon Suk Yeol, C…