inductive unialpha : Type[0] ≝
| bit : bool → unialpha
+| null : unialpha
| comma : unialpha
| bar : unialpha
| grid : unialpha.
definition unialpha_eq ≝
λa1,a2.match a1 with
[ bit x ⇒ match a2 with [ bit y ⇒ ¬ xorb x y | _ ⇒ false ]
+ | null ⇒ match a2 with [ null ⇒ true | _ ⇒ false ]
| comma ⇒ match a2 with [ comma ⇒ true | _ ⇒ false ]
| bar ⇒ match a2 with [ bar ⇒ true | _ ⇒ false ]
| grid ⇒ match a2 with [ grid ⇒ true | _ ⇒ false ] ].
definition DeqUnialpha ≝ mk_DeqSet unialpha unialpha_eq ?.
* [ #x * [ #y cases x cases y normalize % // #Hfalse destruct
| *: normalize % #Hfalse destruct ]
- |*: * [1,5,9,13: #y ] normalize % #H1 destruct % ]
+ |*: * [1,6,11,16: #y ] normalize % #H1 destruct % ]
qed.
-axiom unialpha_unique : uniqueb DeqUnialpha [bit true;bit false;comma;bar;grid] = true.
+lemma unialpha_unique :
+ uniqueb DeqUnialpha [bit true;bit false;null;comma;bar;grid] = true.
+// qed.
+
+lemma unialpha_complete :∀x:DeqUnialpha.
+ memb ? x [bit true;bit false;null;comma;bar;grid] = true.
+* // * //
+qed.
definition FSUnialpha ≝
- mk_FinSet DeqUnialpha [bit true;bit false;comma;bar;grid] unialpha_unique.
+ mk_FinSet DeqUnialpha [bit true;bit false;null;comma;bar;grid]
+ unialpha_unique unialpha_complete.
definition is_bit ≝ λc.match c with [ bit _ ⇒ true | _ ⇒ false ].
+definition is_null ≝ λc.match c with [ null ⇒ true | _ ⇒ false ].
+
definition is_grid ≝ λc.match c with [ grid ⇒ true | _ ⇒ false ].
definition is_bar ≝ λc.match c with [ bar ⇒ true | _ ⇒ false ].
definition is_comma ≝ λc.match c with [ comma ⇒ true | _ ⇒ false ].
+definition bit_or_null ≝ λc.is_bit c ∨ is_null c.