On this day 127 years ago, on April 16, 1898 (March 26, 1898 lunar calendar), the German mathematician Helmut Kneizer was born. Helmut Kneizer (April 16, 1898 - August 23, 1973) was a German mathematician who made many contributions to group theory and topology. The most famous result was the proof of the existence of prime decomposition of three-dimensional manifolds, which also gave rise to the concept of normalsurface. He worked on the solution of f (f (x)) = ex. From 1958 to 1959, he was the director of the Oberwalfach Mathematical Institute. His father, Adolf Kneizer, and his son, Martin Kneizer, were both mathematicians.