• Non-Constructivity in Kan Simplicial Sets 

      Bezem, Marc; Coquand, Thierry; Parmann, Erik (Journal article; Peer reviewed, 2015)
      We give an analysis of the non-constructivity of the following basic result: if X and Y are simplicial sets and Y has the Kan extension property, then Y X also has the Kan extension property. By means of Kripke countermodels ...