Kolchin's problems
Kolchin's problems are a set of unsolved problems in differential algebra, outlined by Ellis Kolchin at the International Congress of Mathematicians in 1966 (Moscow) == Kolchin Catenary Conjecture == The Kolchin Catenary Conjecture is a fundamental open problem in differential algebra related to dimension theory. === Statement === "Let Σ {\displaystyle \Sigma } be a differential algebraic variety of dimension d {\displaystyle d} .