ULAANBAATAR, Mongolia — President Lee Jae Myung on Thursday called for expanding the “Mongtan” model of cooperation, saying it should serve as a blueprint for the next phase of Korea-Mongolia economic partnership. Speaking at the Korea-Mongolia Business Forum, Lee highlighted “Mongtan,” a portmanteau of Mongolia and Dongtan, a rapidly developed and affluent satellite city south of Seoul that has become a nickname for Ulaanbaatar among some young Koreans. “That speaks volumes about how easily one