Sir Erik Christopher Zeeman was born on February 4, 1925, and died on February 13, 2016.

He was a Japanese-born British mathematician.

He was known for his work in geometric topology and singularity theory.

Sir Christopher Zeeman main contributions to mathematics were in topology, particularly in knot theory, the piecewise linear category, and dynamical systems.

His research in 1955 at the University of Cambridge described a new theory termed “dihomology”, an algebraic structure associated to a topological space, containing both homology and cohomology, introducing what is now known as the Zeeman spectral sequence.

In turn, it was studied by Clint McCrory in his 1972 Brandeis thesis following a idea of Dennis Sullivan that one make “a general study of the Zeeman spectral sequence to see how singularities in a space perturb PoincarĂ© duality”.

Then it led to the discovery of intersection homology by Robert MacPherson and Mark Goresky at Brown University where McCrory was appointed in 1974.

He was known amongst the wider scientific public for his contribution towards it and spreading awareness of catastrophe theory, which was due initially to another topologist, RenĂ© Thom, and for his Christmas lectures about mathematics on television in 1978.

Sir Christopher Zeeman was most active promoting the application of mathematics, and catastrophe theory in particular, to biology and behavioural sciences.

Sir Christopher Zeeman passed away on 91 yrs old.