343.lean:27:11-27:16: warning: declaration uses 'sorry'
343.lean:30:24-30:54: error: stuck at solving universe constraints
  max (?u+1) (?u+1) =?= max (?u+1) (?u+1)
while trying to unify
  CatIsh.Obj.{max (max (?u + 1) (?u + 1)) ?u ?u,
      max ((max (?u + 1) (?u + 1)) + 1) ((max ?u ?u) + 1)}
    Catish.{max ?u ?u, max (?u + 1) (?u + 1)}
with
  CatIsh.{max ?u ?u, max (?u + 1) (?u + 1)}