--- /dev/null
+[\lambda z:nat. \lambda h:(le O z). (eq nat O O)]
+match (le_n O): le with
+[ le_n \Rightarrow (refl_equal nat O)
+| (le_S x y) \Rightarrow (refl_equal nat O) ]
+### (* METASENV after disambiguation *)
+
+### (* TERM after disambiguation *)
+
+<[z:nat][h:(le O z)](eq nat O O)>Cases (le_n O) of
+ le_n => (refl_equal nat O)
+ le_S => [x:nat][y:(le O x)](refl_equal nat O)
+end
+### (* TYPE_OF the disambiguated term *)
+([z:nat][h:(le O z)](eq nat O O) O (le_n O))
+### (* REDUCED disambiguated term *)
+(refl_equal nat O)