Acciones

Relación 6

De Razonamiento automático (2016-17)

chapter {* R6: Recorridos de árboles *}

theory R6_Recorridos_de_arboles
imports Main 
begin 

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 1. Definir el tipo de datos arbol para representar los
  árboles binarios que tiene información en los nodos y en las hojas. 
  Por ejemplo, el árbol
          e
         / \
        /   \
       c     g
      / \   / \
     a   d f   3
  se representa por "N e (N c (H a) (H d)) (N g (H f) (H h))".
  --------------------------------------------------------------------- 
*}

(* ivamenjim marpoldia1 manmorjim1 bowma migtermor wilmorort juacabsou serrodcal pabrodmac*)

datatype 'a arbol = H "'a" | N "'a" "'a arbol" "'a arbol"

value "N e (N c (H a) (H d)) (N g (H f) (H h))" 

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 2. Definir la función 
     preOrden :: "'a arbol ⇒ 'a list"
  tal que (preOrden a) es el recorrido pre orden del árbol a. Por
  ejemplo, 
     preOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))
     = [e,c,a,d,g,f,h] 
  --------------------------------------------------------------------- 
*}

(* ivamenjim marpoldia1 pablucoto bowma fraortmoy migtermor wilmorort lucnovdos serrodcal pabrodmac *)

fun preOrden :: "'a arbol ⇒ 'a list" where
  "preOrden (H t) = [t]"
| "preOrden (N t i d) = [t] @ (preOrden i) @ (preOrden d)"

(* danrodcha crigomgom manmorjim1 bowma juacabsou *)
fun preOrden1 :: "'a arbol ⇒ 'a list" where
  "preOrden1 (H x) = [x]"
| "preOrden1 (N x i d) = x#preOrden1 i @ preOrden1 d"

value "preOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))  
      = [e,c,a,d,g,f,h]" 
value "preOrden1 (N e (N c (H a) (H d)) (N g (H f) (H h)))  
      = [e,c,a,d,g,f,h]" 

(* danrodcha *)
lemma "preOrden a = preOrden1 a"
by (induct a) simp_all

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 3. Definir la función 
     postOrden :: "'a arbol ⇒ 'a list"
  tal que (postOrden a) es el recorrido post orden del árbol a. Por
  ejemplo, 
     postOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))
     = [e,c,a,d,g,f,h] 
  --------------------------------------------------------------------- 
*}

(* ivamenjim  danrodcha crigomgom marpoldia1 manmorjim1 pablucoto bowma fraortmoy migtermor wilmorort lucnovdos juacabsou serrodcal pabrodmac *)

fun postOrden :: "'a arbol ⇒ 'a list" where
  "postOrden (H t) = [t]"
| "postOrden (N t i d) = (postOrden i) @ (postOrden d) @ [t]"

value "postOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))
       = [a,d,c,f,h,g,e]"

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 4. Definir la función 
     inOrden :: "'a arbol ⇒ 'a list"
  tal que (inOrden a) es el recorrido in orden del árbol a. Por
  ejemplo, 
     inOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))
     = [a,c,d,e,f,g,h]
  --------------------------------------------------------------------- 
*}

(* ivamenjim crigomgom marpoldia1 pablucoto bowma fraortmoy migtermor wilmorort lucnovdos juacabsou serrodcal pabrodmac *)

fun inOrden :: "'a arbol ⇒ 'a list" where
  "inOrden (H t) = [t]"
| "inOrden (N t i d) = (inOrden i) @ [t] @ (inOrden d)"


(* danrodcha manmorjim1 *)
fun inOrden1 :: "'a arbol ⇒ 'a list" where
  "inOrden1 (H t) = [t]"
| "inOrden1 (N t i d) = inOrden1 i @ t#inOrden1 d"

value "inOrden (N e (N c (H a) (H d)) (N g (H f) (H h)))
       = [a,c,d,e,f,g,h]"
value "inOrden1 (N e (N c (H a) (H d)) (N g (H f) (H h)))
       = [a,c,d,e,f,g,h]"

(* manmorjim1 *)
lemma "inOrden t = inOrden1 t"
apply (induct t)
apply auto
done

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 5. Definir la función 
     espejo :: "'a arbol ⇒ 'a arbol"
  tal que (espejo a) es la imagen especular del árbol a. Por ejemplo, 
     espejo (N e (N c (H a) (H d)) (N g (H f) (H h)))
     = N e (N g (H h) (H f)) (N c (H d) (H a))
  --------------------------------------------------------------------- 
*}

(* ivamenjim danrodcha crigomgom marpoldia1 manmorjim1 pablucoto bowma fraortmoy migtermor wilmorort lucnovdos juacabsou serrodcal pabrodmac *)

fun espejo :: "'a arbol ⇒ 'a arbol" where
  "espejo (H t) = H t"
| "espejo (N t i d) = N t (espejo d) (espejo i)"

value "espejo (N e (N c (H a) (H d)) (N g (H f) (H h))) 
       = N e (N g (H h) (H f)) (N c (H d) (H a))"


text {*  
  --------------------------------------------------------------------- 
  Ejercicio 6. Demostrar que
     preOrden (espejo a) = rev (postOrden a)
  --------------------------------------------------------------------- 
*}

(* ivamenjim migtermor wilmorort juacabsou serrodcal *)

lemma  "preOrden (espejo a) = rev (postOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "preOrden (espejo (N x i d)) = preOrden (N x (espejo d) (espejo i))" by simp
  also have "... = [x] @ (preOrden (espejo d)) @ (preOrden (espejo i))" by simp
  also have "... = [x] @ rev (postOrden d) @ rev (postOrden i)" using h1 h2 by simp 
  finally show "preOrden (espejo (N x i d)) = rev (postOrden (N x i d))" by simp
 
qed

(* danrodcha *)
lemma  "preOrden (espejo a) = rev (postOrden a)"
by (induct a) simp_all

(* danrodcha crigomgom*)
lemma  "preOrden (espejo a) = rev (postOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  have "preOrden (espejo (N x i d)) = preOrden (N x (espejo d) (espejo i))"
    by (simp only: espejo.simps(2))
  also have "… = x#preOrden (espejo d) @ preOrden (espejo i)"
    by (simp only: preOrden.simps(2))
  also have"… = x#rev (postOrden d) @ rev (postOrden i)" 
    using HIi HId by simp
  also have "… = rev (postOrden (N x i d))" by simp
  finally show "?P (N x i d)" by simp
qed

(* danrodcha fraortmoy *)
lemma  "preOrden (espejo a) = rev (postOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  show "?P (N x i d)" using HIi HId by simp
qed

(* bowma *)
lemma  "preOrden (espejo a) = rev (postOrden a)"
apply (induct a)
apply simp_all
done

(* pablucoto marpoldia1*)

lemma  "preOrden (espejo a) = rev (postOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x i d 
  assume h1: "?P i"
  assume h2: "?P d"
  have "preOrden (espejo (N x i d)) = preOrden (N x (espejo d) (espejo i))" by simp
  also have "... = [x] @ (preOrden (espejo d)) @ (preOrden (espejo i))" by simp
  also have "... = [x] @ rev (postOrden d) @ rev (postOrden i)" using h1 h2 by simp
  also have "... = [x] @ rev (postOrden i @ postOrden d)" by simp 
  also have "... = rev ( postOrden i @ postOrden d @ [x] ) " by simp
  also have "... = rev (postOrden (N x i d)) " by simp
  finally show "?P (N x i d)" by simp  
qed

(* bowma *)
lemma  "preOrden (espejo a) = rev (postOrden a)" (is "?p a")
proof (induct a)
fix t
show "?p (H t)" by simp
(* Aquí si le diga "preOrden (espejo (H t)) = rev (postOrden (H t))",isabelle dice: 
proof (prove)
goal (1 subgoal):
 1. preOrden (espejo (H t)) = rev (postOrden (H t)) 
Introduced fixed type variable(s): 'b in "t__" 
No entiendo porqué *)
next 
fix t i d
assume H1: "?p i"
assume H2: "?p d"
have "preOrden (espejo (N t i d)) = preOrden (N t (espejo d) (espejo i))" by simp
also have "... = [t] @ (preOrden (espejo d)) @ (preOrden (espejo i))" by simp
also have "... = [t] @ rev (postOrden d) @ rev (postOrden i)" using H1 H2 by simp
finally show "?p (N t i d)" by simp
qed 

(* fraortmoy lucnovdos pabrodmac*)

lemma  "preOrden (espejo a) = rev (postOrden a)"
by (induct a) auto

(*pabrodmac*)

lemma
  fixes a ::"'b arbol" 
  shows "preOrden (espejo a) = rev (postOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "preOrden (espejo (N x i d)) =  preOrden(N x (espejo d) (espejo i))" by simp
    also have "… = [x]@rev(postOrden d)@rev(postOrden i)" using h1 h2 by simp
    also have "… = rev(postOrden (N x i d))" by simp
    finally show ?thesis .
 qed
qed

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 7. Demostrar que
     postOrden (espejo a) = rev (preOrden a)
  --------------------------------------------------------------------- 
*}

(* ivamenjim crigomgom bowma migtermor wilmorort juacabsou serrodcal *)

lemma "postOrden (espejo a) = rev (preOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "postOrden (espejo (N x i d)) = postOrden (N x (espejo d) (espejo i))" by simp
  also have "... = (postOrden (espejo d)) @ (postOrden (espejo i)) @ [x]" by simp
  also have "... = rev (preOrden d) @ rev (preOrden i) @ [x]" using h1 h2 by simp 
  finally show "postOrden (espejo (N x i d)) = rev (preOrden (N x i d))" by simp
  (* "?p (N x i d)" más corto *)
  
qed

(* danrodcha fraortmoy *)
lemma "postOrden (espejo a) = rev (preOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  show "?P (N x i d)" using HIi HId by simp
qed

(* pablucoto marpoldia1*)
 
lemma "postOrden (espejo a) = rev (preOrden a)"  (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp 
next 
  fix x i d
  assume H1: "?P i"
  assume H2: "?P d"
  have " postOrden (espejo (N x i d)) = postOrden ( N x (espejo d) (espejo i)) " by simp
  also have "... = postOrden (espejo d) @ postOrden (espejo i) @ [x]  " by simp
  also have "... = rev (preOrden d) @ rev (preOrden i) @ [x] " using H1 H2 by simp
  also have "... = rev (preOrden d) @ rev (x # preOrden i)"  by simp
  also have "... = rev (x # preOrden i @ preOrden d)" by simp
  also have "... = rev (preOrden (N x i d)) " by simp
  finally show "?P (N x i d)" by simp
 qed

(* fraortmoy lucnovdos pabrodmac*)
lemma "postOrden (espejo a) = rev (preOrden a)"
by (induct a) auto

(*pabrodmac*)

lemma
  fixes a ::"'b arbol" 
  shows "postOrden (espejo a) = rev (preOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "postOrden (espejo (N x i d)) =  postOrden(N x (espejo d) (espejo i))" by simp
    also have "… =rev(preOrden d)@rev(preOrden i)@[x]" using h1 h2 by simp
    also have "… =rev(preOrden (N x i d))" by simp
    finally show ?thesis.
 qed
qed

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 8. Demostrar que
     inOrden (espejo a) = rev (inOrden a)
  --------------------------------------------------------------------- 
*}

(* ivamenjim crigomgom bowma migtermor wilmorort juacabsou serrodcal *)

theorem "inOrden (espejo a) = rev (inOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "inOrden (espejo (N x i d)) = inOrden (N x (espejo d) (espejo i))" by simp
  also have "... = (inOrden (espejo d)) @ [x] @ (inOrden (espejo i))" by simp
  also have "... = rev (inOrden d) @ [x] @ rev (inOrden i)" using h1 h2 by simp 
  finally show "inOrden (espejo (N x i d)) = rev (inOrden (N x i d))" by simp
qed

(* danrodcha *)
theorem "inOrden (espejo a) = rev (inOrden a)"
by (induct a) simp_all

(* danrodcha *)
theorem "inOrden (espejo a) = rev (inOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  show "?P (N x i d)" using HIi HId by simp
qed

(* pablucoto marpoldia1 *)
theorem "inOrden (espejo a) = rev (inOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x) " by simp
next 
  fix x i d 
  assume HI1: "?P i"
  assume HI2: "?P d"
  have " inOrden (espejo (N x i d)) = inOrden ( N x (espejo d) (espejo i) )" by simp
  also have "... = inOrden (espejo d) @ [x] @ inOrden (espejo i) " by simp
  also have "... = rev (inOrden d) @ [x] @ rev (inOrden i)" using HI1 HI2 by simp
  also have "... = rev (x # inOrden d ) @ rev (inOrden i)" by simp
  also have "... = rev ( inOrden i @ x # inOrden d) " by simp
  also have "... = rev (inOrden (N x i d))" by simp
  finally show "?P (N x i d)" by simp
qed

(* lucnovdos pabrodmac *)
theorem "inOrden (espejo a) = rev (inOrden a)"
by (induct a) auto

(* pabrodmac *)

lemma
  fixes a ::"'b arbol" 
  shows "inOrden (espejo a) = rev (inOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "inOrden (espejo (N x i d)) =  inOrden(N x (espejo d) (espejo i))" by simp
    also have "… =rev(inOrden d)@[x]@rev(inOrden i)" using h1 h2 by simp
    also have "… =rev(inOrden (N x i d))" by simp
    finally show ?thesis .
 qed
qed

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 9. Definir la función 
     raiz :: "'a arbol ⇒ 'a"
  tal que (raiz a) es la raiz del árbol a. Por ejemplo, 
     raiz (N e (N c (H a) (H d)) (N g (H f) (H h))) = e
  --------------------------------------------------------------------- 
*}

(* danrodcha crigomgom manmorjim1 ivamenjim bowma pablucoto migtermor marpoldia1 wilmorort lucnovdos  juacabsou serrodcal*)
fun raiz :: "'a arbol ⇒ 'a" where
  "raiz (H x) = x"
| "raiz (N x i d) = x"

value "raiz (N e (N c (H a) (H d)) (N g (H f) (H h))) = e"

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 10. Definir la función 
     extremo_izquierda :: "'a arbol ⇒ 'a"
  tal que (extremo_izquierda a) es el nodo más a la izquierda del árbol
  a. Por ejemplo,  
     extremo_izquierda (N e (N c (H a) (H d)) (N g (H f) (H h))) = a
  --------------------------------------------------------------------- 
*}

(* danrodcha crigomgom manmorjim1 ivamenjim bowma pablucoto migtermor marpoldia1 wilmorort lucnovdos  juacabsou serrodcal pabrodmac *)
fun extremo_izquierda :: "'a arbol ⇒ 'a" where
  "extremo_izquierda (H x) = x"
| "extremo_izquierda (N x i d) = extremo_izquierda i"

value "extremo_izquierda (N e (N c (H a) (H d)) (N g (H f) (H h))) = a"

(* bowma *)
fun extremo_izquierda_1 :: "'a arbol ⇒ 'a" where
  "extremo_izquierda_1 (H t) = t"
| "extremo_izquierda_1 (N t i d) = hd (inOrden (N t i d))"

(* ivamenjim *)
(* Metaejercicio de demostración. Llamando teorema_13 al teorema del ejercicio 13 *)

lemma "extremo_izquierda a = extremo_izquierda_1 a"
by (induct a, simp_all add: aux_ej12_1 teorema_13)

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 11. Definir la función 
     extremo_derecha :: "'a arbol ⇒ 'a"
  tal que (extremo_derecha a) es el nodo más a la derecha del árbol
  a. Por ejemplo,  
     extremo_derecha (N e (N c (H a) (H d)) (N g (H f) (H h))) = h
  --------------------------------------------------------------------- 
*}

(* danrodcha crigomgom manmorjim1 ivamenjim bowma pablucoto migtermor marpoldia1 wilmorort lucnovdos  juacabsou pabrodmac *)
fun extremo_derecha :: "'a arbol ⇒ 'a" where
  "extremo_derecha (H x) = x"
| "extremo_derecha (N x i d) = extremo_derecha d"

value "extremo_derecha (N e (N c (H a) (H d)) (N g (H f) (H h))) = h"

(* bowma *)
fun extremo_derecha_1 :: "'a arbol ⇒ 'a" where
  "extremo_derecha_1 (H t) = t"
| "extremo_derecha_1 (N t i d) = last (inOrden (N t i d))"

(* ivamenjim *)
(* Metaejercicio de demostración. Llamando teorema_12 al teorema del ejercicio 12 *)

lemma "extremo_derecha a = extremo_derecha_1 a"
by (induct a, simp_all add: aux_ej12_1 teorema_12)

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 12. Demostrar o refutar
     last (inOrden a) = extremo_derecha a
  --------------------------------------------------------------------- 
*}

(* danrodcha *)
lemma aux_ej12: "inOrden a ≠ []"
apply (induct a) 
apply simp
apply simp
done

(* danrodcha pablucoto crigomgom  wilmorort juacabsou *)
theorem "last (inOrden a) = extremo_derecha a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  have "last (inOrden (N x i d)) = last (inOrden i @ [x] @ inOrden d)" 
    by (simp only: inOrden.simps(2))
  also have "… = last (inOrden d)" by (simp add: aux_ej12)
  also have "… = extremo_derecha d" using HId by simp
  also have "… = extremo_derecha (N x i d)" by simp
  finally show "?P (N x i d)" by simp
qed

(* ivamenjim *)

lemma aux_ej12_1: "inOrden a ≠ []"
by (induct a) simp_all 

(* ivamenjim marpoldia1 *)
(* Igual que la anterior, pero poniendo solo by simp en el primer have *)

theorem "last (inOrden a) = extremo_derecha a" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "last (inOrden (N x i d)) = last ((inOrden i) @ [x] @ (inOrden d))" by simp 
  also have "... = last (inOrden d)" by (simp add: aux_ej12_1)
  also have "... = extremo_derecha d" using h2 by simp 
  finally show "last (inOrden (N x i d)) = extremo_derecha (N x i d)" by simp
qed

(* bowma *)
(* Casi lo mismo que el anterior,pero no hace falta suponer "?p i" *)
theorem "last (inOrden a) = extremo_derecha a" (is "?p a")
proof (induct a)
fix t
show "?p (H t)" by simp
next 
fix t i d
assume HI: "?p d"
have "last (inOrden (N t i d)) = last (inOrden i @ [t] @ inOrden d)" by simp
also have "... = last (inOrden d)" by (simp add:aux_ej12)
also have "... = extremo_derecha d" using HI by simp
finally show "?p (N t i d)" by simp
qed

(* lucnovdos*)
(* El mismo que el anterior,pero sin usar patrones *)
theorem "last (inOrden a) = extremo_derecha a"
proof (induct a)
  fix x ::"'a"
  show "last (inOrden (H x)) = extremo_derecha (H x)" by simp
next
  fix x   ::"'a"
  fix i d ::"'a arbol"
  assume HI: "last (inOrden d) = extremo_derecha d"
  have "last (inOrden (N x i d)) = last ((inOrden i) @ [x] @ (inOrden d))" by simp 
  also have "… = last (inOrden d)" by (simp add: aux_ej12)
  also have "… = extremo_derecha d" using HI by simp
  also have "… = extremo_derecha (N x i d)" by simp
  finally show "last (inOrden (N x i d)) = extremo_derecha (N x i d)" by simp
qed

(* migtermor *)
theorem "last (inOrden a) = extremo_derecha a" (is "?P a")
proof (induct a)
 fix h
 show "?P (H h)" by simp
next
 fix n i
 fix d assume HId: "?P d"
 have AUX: "¬ (inOrden d = [])" (is "?Q d")
     proof (induct d)
      fix hd
      show "?Q (H hd)" by simp
     next
     fix nd
     fix id assume HIid: "?Q id"
     fix dd assume HIdd: "?Q dd"
     show "?Q (N nd id dd)" using HIid HIdd by simp
     qed
 have "last (inOrden (N n i d)) = last (inOrden i @[n]@inOrden d)" by simp
 also have "… = last (inOrden d)" using AUX by simp
 also have "… = extremo_derecha d" using HId by simp
 finally show "?P (N n i d)"  by simp
qed

(* pabrodmac *)

lemma Aux_ej12: "inOrden a ≠ []"
by (induct a) auto

(* pabrodmac *)

theorem "last (inOrden a) = extremo_derecha a"
by (induct a)(auto simp add: Aux_ej12)

(* pabrodmac *)

lemma
  fixes a ::"'b arbol" 
  shows "last (inOrden a) = extremo_derecha a" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "last (inOrden (N x i d)) =  last((inOrden i)@ [x] @ (inOrden d))" by simp
    also have "… =last(inOrden d)" by (simp add: Aux_ej12)
    also have "… = extremo_derecha d" using h1 h2 by simp
    also have "… = extremo_derecha (N x i d)" by simp
    finally show ?thesis .
qed
qed

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 13. Demostrar o refutar
     hd (inOrden a) = extremo_izquierda a
  --------------------------------------------------------------------- 
*}

(* danrodcha pablucoto crigomgom juacabsou*)
theorem "hd (inOrden a) = extremo_izquierda a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next
  fix x i d 
  assume HIi: "?P i"
  assume HId: "?P d"
  have "hd (inOrden (N x i d)) = hd (inOrden i @ [x] @ inOrden d)" 
    by (simp only: inOrden.simps(2))
  also have "… = hd (inOrden i)" by (simp add: aux_ej12)
  also have "… = extremo_izquierda i" using HIi by simp
  also have "… = extremo_izquierda (N x i d)" by simp
  finally show "?P (N x i d)" by simp
qed

(* bowma lucnovdos *)
theorem "hd (inOrden a) = extremo_izquierda a" (is "?p a")
proof (induct a)
fix t
show "?p (H t)" by simp
next
fix t i d 
assume HI: "?p i"
have "hd (inOrden (N t i d)) = hd (inOrden i @ [t] @ inOrden d)" by simp
also have "… = hd (inOrden i)" by (simp add: aux_ej12)
also have "… = extremo_izquierda i" using HI by simp
finally show "?p (N t i d)" by simp
qed

(* migtermor *)
theorem "hd (inOrden a) = extremo_izquierda a" (is "?P a")
proof (induct a)
 fix h
 show "?P (H h)" by simp
next
 fix n d
 fix i assume HId: "?P i"
 have AUX: "¬ (inOrden i = [])" (is "?Q i")
     proof (induct i)
      fix hi
      show "?Q (H hi)" by simp
     next
     fix ni
     fix ii assume HIid: "?Q ii"
     fix di assume HIdd: "?Q di"
     show "?Q (N ni ii di)" using HIid HIdd by simp
     qed
 have "hd (inOrden (N n i d)) = hd (inOrden i @[n]@inOrden d)" by simp
 also have "… = hd (inOrden i)" using AUX by simp
 also have "… = extremo_izquierda i" using HId by simp
 finally show "?P (N n i d)"  by simp
qed

(* ivamenjim marpoldia1 wilmorort *)

theorem "hd (inOrden a) = extremo_izquierda a" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "hd (inOrden (N x i d)) = hd ((inOrden i) @ [x] @ (inOrden d))" by simp
  also have "... = hd (inOrden i)" by (simp add: aux_ej12_1)
  also have "... = extremo_izquierda i" using h1 by simp 
  finally show "hd (inOrden (N x i d)) = extremo_izquierda (N x i d)" by simp
qed

(* pabrodmac *)

theorem "hd (inOrden a) = extremo_izquierda a"
by (induct a)(auto simp add: Aux_ej12)

(* pabrodmac *)

lemma
  fixes a ::"'b arbol" 
  shows "hd (inOrden a) = extremo_izquierda a" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "hd (inOrden (N x i d)) =  hd((inOrden i)@ [x] @ (inOrden d))" by simp
    also have "… = hd (inOrden i)"  by (simp add: Aux_ej12)
    also have "… = extremo_izquierda i" using h1 h2 by simp
    also have "… = extremo_izquierda (N x i d)" by simp
    finally show ?thesis .
qed
qed


text {*  
  --------------------------------------------------------------------- 
  Ejercicio 14. Demostrar o refutar
     hd (preOrden a) = last (postOrden a)
  --------------------------------------------------------------------- 
*}

(* danrodcha pabrodmac *)
theorem "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  show "?P (N x i d)" by simp
qed

(* danrodcha *)
theorem "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  assume HIi: "?P i"
  assume HId: "?P d"
  have "hd (preOrden (N x i d)) = hd (x#preOrden i @ preOrden d)"
    by (simp only: preOrden.simps(2))
  also have "… = x" by simp
  also have "… = last (postOrden i @ postOrden d @ [x])" by simp
  also have "… = last (postOrden (N x i d))" 
    by (simp only: postOrden.simps(2))
  finally show "?P (N x i d)" by simp
qed

(* pablucoto crigomgom bowma marpoldia1 wilmorort lucnovdos juacabsou *) (*Similar al anterior*)
theorem "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
next   
  fix x i d
  assume HI1: "?P i"
  assume HI2: "?P d"
  have " hd (preOrden (N x i d)) = hd ([x] @ preOrden i @ preOrden d)"  by simp
  also have "... = x" by simp
  also have "... = last ( postOrden i @ postOrden d @ [x]) " by simp
  also have "... = last ( postOrden (N x i d) )" by simp  
  finally show "?P (N x i d)" by simp
qed

(* migtermor *)
theorem "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
 fix h
 show "?P (H h)" by simp
next
 fix n i d
 have "hd (preOrden (N n (i :: 'a arbol) (d :: 'a arbol))) = hd ([n]@preOrden i@preOrden d)" 
      by simp
 (* Si no especifico que i y d son árboles, salta un error de tipo. Supongo que será por
    no haber asumido hipótesis sobre ellos *)
 also have "… = last (postOrden (N n i d))" by simp
 show "?P (N n i d)" by simp
qed

(* ivamenjim *)

theorem "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "hd (preOrden (N x i d)) = hd ([x] @ (preOrden i) @ (preOrden d))" by simp
  also have "... = hd ([x])" by simp
  finally show "hd (preOrden (N x i d)) = last (postOrden (N x i d))" by simp
qed

(* pabrodmac *)

theorem "hd (preOrden a) = last (postOrden a)"
by (induct a) auto  

(* pabrodmac *)

lemma
  fixes a ::"'b arbol" 
  shows "hd (preOrden a) = last (postOrden a)" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  show "?P (N x i d)"   
  proof -               
    have "hd (preOrden (N x i d) )= x" by simp
    also have "… = last (postOrden (N x i d))" by simp
    finally show ?thesis .
 qed
qed


text {*  
  --------------------------------------------------------------------- 
  Ejercicio 15. Demostrar o refutar
     hd (preOrden a) = raiz a
  --------------------------------------------------------------------- 
*}

(* danrodcha *)
theorem "hd (preOrden a) = raiz a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  assume HIi: "?P i"
  assume HId: "?P d"
  have "hd (preOrden (N x i d)) = hd (x#preOrden i @ preOrden d)"
    by (simp only: preOrden.simps(2))
  also have "… = x" by simp
  also have "… = raiz (N x i d)" by simp
  finally show "?P (N x i d)" by simp
qed

(* danrodcha *)
theorem "hd (preOrden a) = raiz a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  show "?P (N x i d)" by simp
qed

(* pablucoto crigomgom ivamenjim marpoldia1 wilmorort lucnovdos juacabsou *)
theorem "hd (preOrden a) = raiz a" (is "?P a")
proof (induct a) 
  fix x
  show "?P (H x)" by simp
next
  fix x i d
  assume HI1: " ?P i"
  assume HI2: " ?P d"
  have " hd (preOrden (N x i d)) = hd ([x] @ preOrden i @ preOrden d) " by simp
  also have "... = x" by simp
  also have "... = raiz (N x i d)" by simp
  finally show " ?P (N x i d)" by simp
qed

(* bowma *)
(* similar al anterior pero sin suponer "?p d" *)
theorem "hd (preOrden a) = last (postOrden a)" (is "?p a")
proof (induct a)
  fix t
  show "?p (H t)" by simp
next
  fix t i d
  assume HI: "?p i"
  have "hd (preOrden (N t i d)) = hd ([t] @ preOrden i @ preOrden d)" by simp
  also have "… = t" by simp
  also have "… = last (postOrden i @ postOrden d @ [t])" by simp
  also have "… = last (postOrden (N t i d))" by simp
  finally show "?p (N t i d)" by simp
qed

(* migtermor *)
theorem "hd (preOrden a) = raiz a" (is "?P a")
proof (induct a)
 fix h
 show "?P (H h)" by simp
next
 fix n i d
 have "hd (preOrden (N n (i :: 'a arbol) (d :: 'a arbol))) = hd ([n]@preOrden i@preOrden d)"
      by simp
 also have "… = raiz (N n i d)" by simp
 finally show "?P (N n i d)" by simp
qed

(* ivamenjim: sin usar patrones *)

theorem "hd (preOrden a) = raiz a" 
proof (induct a)
  fix x ::"'a"
  show "hd (preOrden (H x)) = raiz (H x)" by simp 
next
  fix x ::"'a"
  fix i ::"'a arbol" assume h1: "hd (preOrden i) = raiz i"
  fix d ::"'a arbol" assume h2: "hd (preOrden d) = raiz d"
  have "hd (preOrden (N x i d)) = hd ([x] @ (preOrden i) @ (preOrden d))" by simp
  also have "... = hd ([x])" by simp
  finally show "hd (preOrden (N x i d)) = raiz (N x i d)" by simp
qed

(* pabrodmac *)

theorem "hd (preOrden a) = raiz a"
by (induct a) auto

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 16. Demostrar o refutar
     hd (inOrden a) = raiz a
  --------------------------------------------------------------------- 
*}

(*crigomgom pablucoto bowma migtermor ivamenjim wilmorort lucnovdos juacabsou *)
theorem "hd (inOrden a) = raiz a"
quickcheck
oops

(* danrodcha:
Auto Quickcheck found a counterexample:
  a = N a⇩1 (H a⇩2) (H a⇩1)
Evaluated terms:
  hd (inOrden a) = a⇩2
  raiz a = a⇩1 *)

(* ivamenjim marpoldia1 *)

theorem "hd (inOrden a) = raiz a" (is "?P a")
proof (induct a)
  fix x 
  show "?P (H x)" by simp 
next
  fix x 
  fix i assume h1: "?P i"
  fix d assume h2: "?P d"
  have "hd (inOrden (N x i d)) = hd ((inOrden i) @ [x] @ (inOrden d))" by simp
  also have "... = hd (inOrden i)" by (simp add: aux_ej12_1) 
  (* Perdemos la x, luego se refuta el enunciado del teorema *)
qed

text {*  
  --------------------------------------------------------------------- 
  Ejercicio 17. Demostrar o refutar
     last (postOrden a) = raiz a
  --------------------------------------------------------------------- 
*}

(* danrodcha *)
theorem "last (postOrden a) = raiz a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  show "?P (N x i d)" by simp
qed

(* danrodcha *)
theorem "last (postOrden a) = raiz a" (is "?P a")
proof (induct a)
  fix x
  show "?P (H x)" by simp
  fix x i d
  assume HIi: "?P i"
  assume HId: "?P d"
  have "last (postOrden (N x i d)) = last (postOrden i @ postOrden d @ [x])"
    by (simp only: postOrden.simps(2))
  also have "… = x" by simp
  also have "… = raiz (N x i d)" by (simp only: raiz.simps(2))
  finally show "?P (N x i d)" by simp
qed

(* pablucoto crigomgom ivamenjim marpoldia1 wilmorort lucnovdos juacabsou *) (*Similar al anterior*)

theorem "last (postOrden a) = raiz a" (is "?P a")
proof (induct a )
  fix x
  show "?P (H x)" by simp
next 
  fix x i d
  assume HI1: "?P i"
  assume HI2: "?P d"
  have "last (postOrden (N x i d)) = last ( postOrden i @ postOrden d @ [x])" by simp
  also have "... = x" by simp
  also have "... = raiz (N x i d) " by simp
  finally show " ?P (N x i d)" by simp
qed

(* bowma *)
(* También sin usar el supuesto "?p d" *)
theorem "last (postOrden a) = raiz a" (is "?p a")
proof (induct a)
fix t
show "?p (H t)" by simp
next
fix t i d
assume "?p i"
(* si quito este supuesto, hay error pero no sé dónde se lo está usando *)
have "last (postOrden (N t i d)) = last (postOrden i @ postOrden d @ [t])" by simp
also have "... = t" by simp
also have "... = raiz (N t i d)" by simp
finally show "?p (N t i d)" by simp
qed

(* migtermor *)
theorem "last (postOrden a) = raiz a" (is "?P a")
proof (induct a)
 fix h
 show "?P (H h)" by simp
next
 fix n i d
 have "last (postOrden (N n (i :: 'a arbol) (d :: 'a arbol))) = 
       last (postOrden i@postOrden d@[n])" by simp
 also have "… = raiz (N n i d)" by simp
 finally show "?P (N n i d)" by simp
qed

(* ivamenjim: sin usar patrones *)

theorem "last (postOrden a) = raiz a" 
proof (induct a)
  fix x::"'a" 
  show "last (postOrden (H x)) = raiz (H x)" by simp 
next
  fix x::"'a"  
  fix i::"'a arbol" assume h1: "last (postOrden i) = raiz i"
  fix d::"'a arbol" assume h2: "last (postOrden d) = raiz d"
  have "last (postOrden (N x i d)) = last ((postOrden i) @ (postOrden d) @ [x])" by simp
  also have "... = last ([x])" by simp 
  finally show "last (postOrden (N x i d)) = raiz (N x i d)" by simp
qed

end