1 inductive True: Prop \def
4 inductive False: Prop \def .
6 definition Not: Prop \to Prop \def
7 \lambda A:Prop. (A \to False).
9 theorem absurd : \forall A,C:Prop. A \to Not A \to C.
10 intro.cut False.elim Hcut.apply H1.assumption.
13 inductive And (A,B:Prop) : Prop \def
14 conj : A \to B \to (And A B).
16 theorem proj1: \forall A,B:Prop. (And A B) \to A.
17 intro. elim H. assumption.
20 theorem proj2: \forall A,B:Prop. (And A B) \to A.
21 intro. elim H. assumption.
24 inductive Or (A,B:Prop) : Prop \def
25 or_introl : A \to (Or A B)
26 | or_intror : B \to (Or A B).
28 inductive ex (A:Type) (P:A \to Prop) : Prop \def
29 ex_intro: \forall x:A. P x \to ex A P.
31 inductive ex2 (A:Type) (P,Q:A \to Prop) : Prop \def
32 ex_intro2: \forall x:A. P x \to Q x \to ex2 A P Q.
34 inductive eq (A:Type) (x:A) : A \to Prop \def
35 refl_equal : eq A x x.
37 theorem sym_eq : \forall A:Type.\forall x,y:A. eq A x y \to eq A y x.
38 intro. elim H. apply refl_equal.
41 theorem trans_eq : \forall A:Type.
42 \forall x,y,z:A. eq A x y \to eq A y z \to eq A x z.
43 intro.elim H1.assumption.
46 theorem f_equal: \forall A,B:Type.\forall f:A\to B.
47 \forall x,y:A. eq A x y \to eq B (f x) (f y).
48 intro.elim H.apply refl_equal.
51 theorem f_equal2: \forall A,B,C:Type.\forall f:A\to B \to C.
52 \forall x1,x2:A. \forall y1,y2:B.
53 eq A x1 x2\to eq B y1 y2\to eq C (f x1 y1) (f x2 y2).
54 intro.elim H1.elim H.apply refl_equal.
57 inductive nat : Set \def
61 definition pred: nat \to nat \def
62 \lambda n:nat. match n with
64 | (S u) \Rightarrow u ].
66 theorem pred_Sn : \forall n:nat.
67 (eq nat n (pred (S n))).
68 intro.apply refl_equal.
71 theorem injective_S : \forall n,m:nat.
72 (eq nat (S n) (S m)) \to (eq nat n m).
73 intro.(elim (sym_eq ? ? ? (pred_Sn n))).(elim (sym_eq ? ? ? (pred_Sn m))).
74 apply f_equal. assumption.
77 theorem not_eq_S : \forall n,m:nat.
78 Not (eq nat n m) \to Not (eq nat (S n) (S m)).
79 intro. simplify.intro.
80 apply H.apply injective_S.assumption.
83 definition not_zero : nat \to Prop \def
87 | (S p) \Rightarrow True ].
89 theorem O_S : \forall n:nat. Not (eq nat O (S n)).
91 cut (not_zero O).exact Hcut.elim (sym_eq ? ? ? H).
95 theorem n_Sn : \forall n:nat. Not (eq nat n (S n)).
96 intro.elim n.apply O_S.apply not_eq_S.assumption.
100 definition plus : nat \to nat \to nat \def
101 let rec plus (n,m:nat) \def
104 | (S p) \Rightarrow S (plus p m) ]
108 theorem plus_n_O: \forall n:nat. eq nat n (plus n O).
109 intro.elim n.simplify.apply refl_equal.simplify.apply f_equal.assumption.
112 theorem plus_n_Sm : \forall n,m:nat. eq nat (S (plus n m)) (plus n (S m)).
113 intro.elim n.simplify.apply refl_equal.simplify.apply f_equal.assumption.
116 theorem sym_plus: \forall n,m:nat. eq nat (plus n m) (plus m n).
117 intro.elim n.simplify.apply plus_n_O.
118 simplify.elim (sym_eq ? ? ? H).apply plus_n_Sm.
122 \forall n,m,p:nat. eq nat (plus (plus n m) p) (plus n (plus m p)).
123 intro.elim n.simplify.apply refl_equal.simplify.apply f_equal.assumption.
126 definition times : nat \to nat \to nat \def
127 let rec times (n,m:nat) \def
130 | (S p) \Rightarrow (plus m (times p m)) ]
134 theorem times_n_O: \forall n:nat. eq nat O (times n O).
135 intro.elim n.simplify.apply refl_equal.simplify.assumption.
139 \forall n,m:nat. eq nat (plus n (times n m)) (times n (S m)).
140 intro.elim n.simplify.apply refl_equal.
141 simplify.apply f_equal.elim H.
142 apply trans_eq ? ? (plus (plus e m) (times e m)).apply sym_eq.
143 apply assoc_plus.apply trans_eq ? ? (plus (plus m e) (times e m)).
145 apply sym_plus.apply refl_equal.apply assoc_plus.
149 \forall n,m:nat. eq nat (times n m) (times m n).
150 intro.elim n.simplify.apply times_n_O.
151 simplify.elim (sym_eq ? ? ? H).apply times_n_Sm.
154 definition minus : nat \to nat \to nat \def
155 let rec minus (n,m:nat) \def
156 [\lambda n:nat.nat] match n:nat with
159 [\lambda n:nat.nat] match m:nat with
161 | (S q) \Rightarrow minus p q ]]
166 \forall n:nat.\forall P:nat \to Prop.
167 P O \to (\forall m:nat. P (S m)) \to P n.
168 intro.elim n.assumption.apply H1.
171 theorem nat_double_ind :
172 \forall R:nat \to nat \to Prop.
173 (\forall n:nat. R O n) \to
174 (\forall n:nat. R (S n) O) \to
175 (\forall n,m:nat. R n m \to R (S n) (S m)) \to \forall n,m:nat. R n m.
176 intro.cut \forall m:nat.R n m.apply Hcut.elim n.apply H.
177 apply nat_case m1.apply H1.intro.apply H2. apply H3.
180 inductive le (n:nat) : nat \to Prop \def
182 | le_S : \forall m:nat. le n m \to le n (S m).
184 theorem trans_le: \forall n,m,p:nat. le n m \to le m p \to le n p.
187 apply le_S.assumption.
190 theorem le_n_S: \forall n,m:nat. le n m \to le (S n) (S m).
191 intro.elim H.alias id "le_n" = "cic:/matita/andrea/le.ind#xpointer(1/1/1)".
192 apply le_n.apply le_S.assumption.
195 theorem le_O_n : \forall n:nat. le O n.
196 intro.elim n.apply le_n.apply le_S. assumption.
199 theorem le_n_Sn : \forall n:nat. le n (S n).
200 intro. apply le_S.apply le_n.
203 theorem le_pred_n : \forall n:nat. le (pred n) n.
204 intro.elim n.simplify.apply le_n.simplify.
208 theorem not_zero_le : \forall n,m:nat. (le (S n) m ) \to not_zero m.
209 intro.elim H.exact I.exact I.
212 theorem le_Sn_O: \forall n:nat. Not (le (S n) O).
213 intro.simplify.intro.apply not_zero_le ? O H.
216 theorem le_n_O_eq : \forall n:nat. (le n O) \to (eq nat O n).
217 intro.cut (le n O) \to (eq nat O n).apply Hcut. assumption.
218 elim n.apply refl_equal.apply False_ind.apply (le_Sn_O ? H2).
221 theorem le_S_n : \forall n,m:nat. le (S n) (S m) \to le n m.
222 intro.cut le (pred (S n)) (pred (S m)).exact Hcut.
223 elim H.apply le_n.apply trans_le ? (pred x).assumption.
227 theorem le_Sn_n : \forall n:nat. Not (le (S n) n).
228 intro.elim n.apply le_Sn_O.simplify.intro.
229 cut le (S e) e.apply H.assumption.apply le_S_n.assumption.
232 theorem le_antisym : \forall n,m:nat. (le n m) \to (le m n) \to (eq nat n m).
233 intro.cut (le n m) \to (le m n) \to (eq nat n m).exact Hcut H H1.
234 apply nat_double_ind (\lambda n,m.((le n m) \to (le m n) \to eq nat n m)).
235 intro.whd.intro.alias id "le_n_O_eq" = "cic:/matita/andrea/le_n_O_eq.con".
236 apply le_n_O_eq.assumption.
237 intro.whd.intro.apply sym_eq.apply le_n_O_eq.assumption.
238 intro.whd.intro.apply f_equal.apply H2.
239 apply le_S_n.assumption.
240 apply le_S_n.assumption.
243 inductive bool : Set \def
247 definition notn : bool \to bool \def
250 [ true \Rightarrow false
251 | false \Rightarrow true ].
253 definition andb : bool \to bool \to bool\def
257 match b2 with [true \Rightarrow true | false \Rightarrow false]
258 | false \Rightarrow false ].
260 definition orb : bool \to bool \to bool\def
264 match b2 with [true \Rightarrow true | false \Rightarrow false]
265 | false \Rightarrow false ].
267 definition leb : nat \to nat \to bool \def
268 let rec leb (n,m:nat) \def
269 [\lambda n:nat.bool] match n:nat with
272 [\lambda n:nat.bool] match m:nat with
273 [ O \Rightarrow false
274 | (S q) \Rightarrow leb p q]]
277 definition if_then_else : bool \to Prop \to Prop \to Prop \def
278 \lambda b:bool.\lambda P,Q:Prop.
281 | false \Rightarrow Q].
283 theorem le_dec: \forall n,m:nat. if_then_else (leb n m) (le n m) (Not (le n m)).
285 apply (nat_double_ind
286 (\lambda n,m:nat. if_then_else (leb n m) (le n m) (Not (le n m))) ? ? ? n m).
287 intro.whd.apply le_O_n.intro.whd.apply le_Sn_O.
293 \lambda b:bool. [\lambda x:bool.Prop] match b:bool with
294 [ true \Rightarrow (le n1 m1)
295 | false \Rightarrow (Not(le n1 m1))]
299 [\lambda x:bool.Prop] match b:bool with
300 [ true \Rightarrow (le (S n1) (S m1))
301 | false \Rightarrow (Not(le (S n1) (S m1)))]
307 \lambda b:bool. [\lambda x:bool.Prop] match b:bool with
308 [ true \Rightarrow (le n1 m1)
309 | false \Rightarrow (Not(le n1 m1))]
313 [\lambda x:bool.Prop] match b:bool with
314 [ true \Rightarrow (le (S n1) (S m1))
315 | false \Rightarrow (Not(le (S n1) (S m1)))]
318 match (leb n1 m1) : bool with
319 [ true \Rightarrow \lambda p:(le n1 m1). le_n_S n1 m1 p
320 | false \Rightarrow \lambda p:(Not(le n1 m1)). \lambda q:(le (S n1) (S m1)).p(le_S_n n1 m1 q)]
325 cut (eq bool (leb n1 m1) (leb (S n1) (S m1))).
327 simplify.apply refl_equal.
332 (Not (le (S n1) ( S m1)) )).
333 apply Hcut1.elim Hcut.simplify.
334 check ([\lambda b:bool. [\lambda b:bool.Prop]match (b:bool) with
336 (if_then_else b (le n1 m1) (Not (le n1 m1)))
338 (if_then_else b (le n1 m1) (Not (le n1 m1)))
341 match (leb n1 m1) : bool with
342 [ true \Rightarrow H | false \Rightarrow H ]).
346 [\lambda b:bool. match (b:bool) with
348 (if_then_else b (le (S n1 ) (S m1)) (Not ((le (S n1) (S m1)))))
350 (if_then_else b (le (S n1 ) (S m1)) (Not ((le (S n1) (S m1)))))
353 match (leb n1 m1) : bool with
354 [ true \Rightarrow le_n_S n1 m1 H
356 (\lambda p:(le (S n1) (S m1)).H (le_S_n n1 m1 p))]).
361 elim n.simplify.apply le_O_n.elim m.
362 simplify.apply le_Sn_O.simplify.
363 cut (match (leb e e1):bool with
364 [true \Rightarrow (eq bool (leb e e1) true)
365 | false \Rightarrow (eq bool (leb e e1) false)]).
367 exact [\lambda b:bool. match b with
368 [true \Rightarrow (eq bool b true)
369 | false \Rightarrow (eq bool b false)]] match (leb e e1):bool with
370 [true \Rightarrow refl_equal bool true
371 | false \Rightarrow refl_equal bool false].