SetDirectory["~/Factorisation"];
<<kappaLib.m
<<helper.m

Fresnel surface can decompose into second order surfaces without having a unqiue decomposition

vars={x0,x1,x2,x3};
kappa=emMatrixToKappa[DiagonalMatrix[{-1,1,0,-1,1,0}]];

fr=emKappaToFresnel[kappa,vars]

printNotebook["NonUniqueDecomposition.pdf"]