Question: How many places of higher learning are in the city where the Yongle emperor greeted the person to whom the edict was addressed?

Knowledge 1: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
During his travels beginning in 1403, Deshin Shekpa was induced by further exhortations by the Ming court to visit Nanjing by April 10, 1407. Norbu writes that the Yongle Emperor, following the tradition of Mongol emperors and their reverence for the Sakya lamas, showed an enormous amount of deference towards Deshin Shekpa. The Yongle Emperor came out of the palace in Nanjing to greet the Karmapa and did not require him to kowtow like a tributary vassal. According to Karma Thinley, the emperor gave the Karmapa the place of honor at his left, and on a higher throne than his own. Rossabi and others describe a similar arrangement made by Kublai Khan and the Sakya Phagpa lama, writing that Kublai would "sit on a lower platform than the Tibetan cleric" when receiving religious instructions from him. [SEP] Knowledge 3: Nanjing
Nanjing has been the educational centre in southern China for more than 1700 years. There are 75 institutions of higher learning till 2013. The number of National key laboratories, National key disciplines and the academicians of Chinese Academy of Sciences and Chinese Academy of Engineering all rank third in the nation. It boasts some of the most prominent educational institutions in the region, some of which are listed as follows:
Knowledge 1: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
Throughout the following month, the Yongle Emperor and his court showered the Karmapa with presents. At Linggu Temple in Nanjing, he presided over the religious ceremonies for the Yongle Emperor's deceased parents, while twenty-two days of his stay were marked by religious miracles that were recorded in five languages on a gigantic scroll that bore the Emperor's seal. During his stay in Nanjing, Deshin Shekpa was bestowed the title "Great Treasure Prince of Dharma" by the Yongle Emperor. Elliot Sperling asserts that the Yongle Emperor, in bestowing Deshin Shekpa with the title of "King" and praising his mystical abilities and miracles, was trying to build an alliance with the Karmapa as the Mongols had with the Sakya lamas, but Deshin Shekpa rejected the Yongle Emperor's offer. In fact, this was the same title that Kublai Khan had offered the Sakya Phagpa lama, but Deshin Shekpa persuaded the Yongle Emperor to grant the title to religious leaders of other Tibetan Buddhist sects. [SEP] Knowledge 3: Nanjing
Nanjing has been the educational centre in southern China for more than 1700 years. There are 75 institutions of higher learning till 2013. The number of National key laboratories, National key disciplines and the academicians of Chinese Academy of Sciences and Chinese Academy of Engineering all rank third in the nation. It boasts some of the most prominent educational institutions in the region, some of which are listed as follows:
Knowledge 1: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
During his travels beginning in 1403, Deshin Shekpa was induced by further exhortations by the Ming court to visit Nanjing by April 10, 1407. Norbu writes that the Yongle Emperor, following the tradition of Mongol emperors and their reverence for the Sakya lamas, showed an enormous amount of deference towards Deshin Shekpa. The Yongle Emperor came out of the palace in Nanjing to greet the Karmapa and did not require him to kowtow like a tributary vassal. According to Karma Thinley, the emperor gave the Karmapa the place of honor at his left, and on a higher throne than his own. Rossabi and others describe a similar arrangement made by Kublai Khan and the Sakya Phagpa lama, writing that Kublai would "sit on a lower platform than the Tibetan cleric" when receiving religious instructions from him. [SEP] Knowledge 3: Yuan dynasty
When the Mongols placed the Uighurs of the Kingdom of Qocho over the Koreans at the court the Korean King objected, then the Mongol Emperor Kublai Khan rebuked the Korean King, saying that the Uighur King of Qocho was ranked higher than the Karluk Kara-Khanid ruler, who in turn was ranked higher than the Korean King, who was ranked last, because the Uighurs surrendered to the Mongols first, the Karluks surrendered after the Uighurs, and the Koreans surrendered last, and that the Uighurs surrendered peacefully without violently resisting.

Answer: 75