Jan Willem Klop

Jan Willem Klop (19 December 1945 – 28 September 2025) was a Dutch mathematician who was professor of applied logic at Vrije Universiteit in Amsterdam. He held a Ph.D. in mathematical logic from Utrecht University. Klop is known for his work on the algebra of communicating processes, term re-writing and infinitary lambda calculus, as co-author of TeReSe and for his fixed point combinator

Yk = (L L L L L L L L L L L L L L L L L L L L L L L L L L)

where

L = λabcdefghijklmnopqstuvwxyzr. (r (t h i s i s a f i x e d p o i n t c o m b i n a t o r))

Klop became a member of the Royal Netherlands Academy of Arts and Sciences in 2003. He died on 28 September 2025, at the age of 79.

Selected publications

— preceding technical report FVI 86-03 — preceding technical report IEICE COMP 88-90