Quantizing the discrete Painlev\'e VI equation : The Lax formalism
  A discretization of Painlev\'e VI equation was obtained by Jimbo and Sakai in 1996. There are two ways to quantize it: 1) use the affine Weyl group symmetry (of $D_5^{(1)}$) (Hasegawa, 2011), 2) Lax formalism i.e. monodromy preserving point of view. It turns out that the second approach is also successful and gives the same quantization as in the first approach. 
Koji Hasegawa
math.QA math-ph math.MP nlin.SI