@Unpublished{alti:klr00, author = {Thorsten Altenkirch}, title = {Notes on definability and {Kripke Logical Relations}}, note = {available from {\tt http://www.cs.nott.ac.uk/\~{}txa/publ/klr00.pdf}}, OPTkey = {}, OPTmonth = {}, year = {2000}, www = {http://www.cs.nott.ac.uk/~txa/publ/klr00.pdf}, OPTannote = {} }