A Jordan scenario is behind the Van Hove scenario. Towards a quantum   chemical theory of high temperature superconductivity
  It is suggested that the appearance of Jordan blocks in the normal form of the recursion (transfer) matrix is responsible for high temperature superconductivity and related phenomena. Several published observations are discussed to support this idea. The draft of a quantum chemical theory is given for a more complete verification. Keywords: Jordan scenario, Van Hove scenario, high temperature superconductivity. Short title: Jordan scenario of high temperature superconductivity. 
G. Biczo (Central Research Institute of Chemistry, Hungarian Academy   of Sciences, Budapest, Hungary)