Mathematical Structures of Joseonmathematician

hearty gratitude on his ninetieth birthday From the mid 17th century, Joseon mathematics had a new beginning and devel-oped along two directions, namely the traditional mathematics and one influenced by western mathematics. A great Joseon mathematician if not the greatest, Hong JeongHa was able to complete the Song–Yuan mathematics in his book GuIlJib based on his studies of merely Suanxue Qimeng, YangHui Suanfa and Suanfa Tong-zong. Although Hong JeongHa did not deal with the systems of equations of higher degrees and general systems of linear congruences, he had the more advanced the-ories of right triangles and equations together with the number theory. The pur-pose of this paper is to show that Hong was able to realize the completion through his perfect understanding of mathematical structures