December 12, 1832 (Imjin October 21), the Norwegian mathematician Ciro born.

1832 12 12, the Norwegian mathematician Peter Ludvig Medel �� Ciro was born, he proved Ciro Theorem.
1832 12 12 -1918, September 7) is a Norwegian mathematician, proved important basic theorems of group theory, is Ciro theorem. Ciro birth and death of Christiania (now Oslo).
Ciro studying at the University of Christiania, a degree in mathematics in 1852. From 1858 to 1898 as a school teacher in friedrichshall (now halden). 1862 at the University of Christiania contemporary lesson lecturer, professor Galois theory. When he proposed to guide him found Ciro subgroup and Theorem. In 1872, he published a Triple theorem, now known as the Western Roman theorem. Was not proved, decades later, he provided the proof. From from
1873 to 1881, he and Suofei Si Lee with editing Niels Abel papers. In accordance with the said Lee, Ciro made decisive work.
Ciro in 1894 to become editor of the mathematics journal "Acta Mathematica", received an honorary doctorate of the University of Copenhagen. Lee in the University of Christiania Ciro set up a Special Lecturer Ciro taught at the university since 1898.