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	<title>Rel 7 - Historial de revisiones</title>
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	<updated>2026-07-17T10:54:59Z</updated>
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	<entry>
		<id>https://www.glc.us.es/~jalonso/LMF2013/index.php?title=Rel_7&amp;diff=378&amp;oldid=prev</id>
		<title>Jalonso: Protegió «Rel 7» ([edit=sysop] (indefinido) [move=sysop] (indefinido))</title>
		<link rel="alternate" type="text/html" href="https://www.glc.us.es/~jalonso/LMF2013/index.php?title=Rel_7&amp;diff=378&amp;oldid=prev"/>
		<updated>2013-04-09T18:59:07Z</updated>

		<summary type="html">&lt;p&gt;Protegió «&lt;a href=&quot;/~jalonso/LMF2013/index.php/Rel_7&quot; title=&quot;Rel 7&quot;&gt;Rel 7&lt;/a&gt;» ([edit=sysop] (indefinido) [move=sysop] (indefinido))&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;es&quot;&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Revisión anterior&lt;/td&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revisión del 18:59 9 abr 2013&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-notice&quot; lang=&quot;es&quot;&gt;&lt;div class=&quot;mw-diff-empty&quot;&gt;(Sin diferencias)&lt;/div&gt;
&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;</summary>
		<author><name>Jalonso</name></author>
		
	</entry>
	<entry>
		<id>https://www.glc.us.es/~jalonso/LMF2013/index.php?title=Rel_7&amp;diff=376&amp;oldid=prev</id>
		<title>Jalonso: Página creada con &#039;&lt;source lang=&quot;Isar&quot;&gt; header {* R7: Deducción natural en lógica de primer orden con Isabelle/HOL *}  theory R7 imports Main  begin  text {*   Demostrar o refutar los siguientes...&#039;</title>
		<link rel="alternate" type="text/html" href="https://www.glc.us.es/~jalonso/LMF2013/index.php?title=Rel_7&amp;diff=376&amp;oldid=prev"/>
		<updated>2013-04-09T18:58:06Z</updated>

		<summary type="html">&lt;p&gt;Página creada con &amp;#039;&amp;lt;source lang=&amp;quot;Isar&amp;quot;&amp;gt; header {* R7: Deducción natural en lógica de primer orden con Isabelle/HOL *}  theory R7 imports Main  begin  text {*   Demostrar o refutar los siguientes...&amp;#039;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;Página nueva&lt;/b&gt;&lt;/p&gt;&lt;div&gt;&amp;lt;source lang=&amp;quot;Isar&amp;quot;&amp;gt;&lt;br /&gt;
header {* R7: Deducción natural en lógica de primer orden con Isabelle/HOL *}&lt;br /&gt;
&lt;br /&gt;
theory R7&lt;br /&gt;
imports Main &lt;br /&gt;
begin&lt;br /&gt;
&lt;br /&gt;
text {*&lt;br /&gt;
  Demostrar o refutar los siguientes lemas usando sólo las reglas&lt;br /&gt;
  básicas de deducción natural de la lógica proposicional, de los&lt;br /&gt;
  cuantificadores y de la igualdad: &lt;br /&gt;
  · conjI:      ⟦P; Q⟧ ⟹ P ∧ Q&lt;br /&gt;
  · conjunct1:  P ∧ Q ⟹ P&lt;br /&gt;
  · conjunct2:  P ∧ Q ⟹ Q  &lt;br /&gt;
  · notnotD:    ¬¬ P ⟹ P&lt;br /&gt;
  · mp:         ⟦P ⟶ Q; P⟧ ⟹ Q &lt;br /&gt;
  · impI:       (P ⟹ Q) ⟹ P ⟶ Q&lt;br /&gt;
  · disjI1:     P ⟹ P ∨ Q&lt;br /&gt;
  · disjI2:     Q ⟹ P ∨ Q&lt;br /&gt;
  · disjE:      ⟦P ∨ Q; P ⟹ R; Q ⟹ R⟧ ⟹ R &lt;br /&gt;
  · FalseE:     False ⟹ P&lt;br /&gt;
  · notE:       ⟦¬P; P⟧ ⟹ R&lt;br /&gt;
  · notI:       (P ⟹ False) ⟹ ¬P&lt;br /&gt;
  · iffI:       ⟦P ⟹ Q; Q ⟹ P⟧ ⟹ P = Q&lt;br /&gt;
  · iffD1:      ⟦Q = P; Q⟧ ⟹ P &lt;br /&gt;
  · iffD2:      ⟦P = Q; Q⟧ ⟹ P&lt;br /&gt;
  · ccontr:     (¬P ⟹ False) ⟹ P&lt;br /&gt;
&lt;br /&gt;
  · allI:       ⟦∀x. P x; P x ⟹ R⟧ ⟹ R&lt;br /&gt;
  · allE:       (⋀x. P x) ⟹ ∀x. P x&lt;br /&gt;
  · exI:        P x ⟹ ∃x. P x&lt;br /&gt;
  · exE:        ⟦∃x. P x; ⋀x. P x ⟹ Q⟧ ⟹ Q&lt;br /&gt;
&lt;br /&gt;
  · refl:       t = t&lt;br /&gt;
  · subst:      ⟦s = t; P s⟧ ⟹ P t&lt;br /&gt;
  · trans:      ⟦r = s; s = t⟧ ⟹ r = t&lt;br /&gt;
  · sym:        s = t ⟹ t = s&lt;br /&gt;
  · not_sym:    t ≠ s ⟹ s ≠ t&lt;br /&gt;
  · ssubst:     ⟦t = s; P s⟧ ⟹ P t&lt;br /&gt;
  · box_equals: ⟦a = b; a = c; b = d⟧ ⟹ a: = d&lt;br /&gt;
  · arg_cong:   x = y ⟹ f x = f y&lt;br /&gt;
  · fun_cong:   f = g ⟹ f x = g x&lt;br /&gt;
  · cong:       ⟦f = g; x = y⟧ ⟹ f x = g y&lt;br /&gt;
*}&lt;br /&gt;
&lt;br /&gt;
text {*&lt;br /&gt;
  Se usarán las reglas notnotI y mt que demostramos a continuación.&lt;br /&gt;
  *}&lt;br /&gt;
&lt;br /&gt;
lemma notnotI: &amp;quot;P ⟹ ¬¬ P&amp;quot;&lt;br /&gt;
by auto&lt;br /&gt;
&lt;br /&gt;
lemma mt: &amp;quot;⟦F ⟶ G; ¬G⟧ ⟹ ¬F&amp;quot;&lt;br /&gt;
by auto&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 1. Demostrar&lt;br /&gt;
       ∀x. P x ⟶ Q x ⊢ (∀x. P x) ⟶ (∀x. Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_1: &lt;br /&gt;
  assumes &amp;quot;∀x. P x ⟶ Q x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;(∀x. P x) ⟶ (∀x. Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 2. Demostrar&lt;br /&gt;
       ∃x. ¬(P x) ⊢ ¬(∀x. P x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_2: &lt;br /&gt;
  assumes &amp;quot;∃x. ¬(P x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;¬(∀x. P x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 3. Demostrar&lt;br /&gt;
       ∀x. P x ⊢ ∀y. P y&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_3: &lt;br /&gt;
  assumes &amp;quot;∀x. P x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀y. P y&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 4. Demostrar&lt;br /&gt;
       ∀x. P x ⟶ Q x ⊢ (∀x. ¬(Q x)) ⟶ (∀x. ¬ (P x))&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_4: &lt;br /&gt;
  assumes &amp;quot;∀x. P x ⟶ Q x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;(∀x. ¬(Q x)) ⟶ (∀x. ¬ (P x))&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 5. Demostrar&lt;br /&gt;
       ∀x. P x  ⟶ ¬(Q x) ⊢ ¬(∃x. P x ∧ Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_5: &lt;br /&gt;
  assumes &amp;quot;∀x. P x  ⟶ ¬(Q x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;¬(∃x. P x ∧ Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 6. Demostrar&lt;br /&gt;
       ∀x y. P x y ⊢ ∀u v. P u v&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_6: &lt;br /&gt;
  assumes &amp;quot;∀x y. P x y&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀u v. P u v&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 7. Demostrar&lt;br /&gt;
       ∃x y. P x y ⟹ ∃u v. P u v&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_7: &lt;br /&gt;
  assumes &amp;quot;∃x y. P x y&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃u v. P u v&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 8. Demostrar&lt;br /&gt;
       ∃x. ∀y. P x y ⊢ ∀y. ∃x. P x y&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_8: &lt;br /&gt;
  assumes &amp;quot;∃x. ∀y. P x y&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀y. ∃x. P x y&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 9. Demostrar&lt;br /&gt;
       ∃x. P a ⟶ Q x ⊢ P a ⟶ (∃x. Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_9: &lt;br /&gt;
  assumes &amp;quot;∃x. P a ⟶ Q x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;P a ⟶ (∃x. Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 10. Demostrar&lt;br /&gt;
       P a ⟶ (∃x. Q x) ⊢ ∃x. P a ⟶ Q x &lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_10: &lt;br /&gt;
  fixes P Q :: &amp;quot;&amp;#039;b ⇒ bool&amp;quot; &lt;br /&gt;
  assumes &amp;quot;P a ⟶ (∃x. Q x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃x. P a ⟶ Q x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 11. Demostrar&lt;br /&gt;
       (∃x. P x) ⟶ Q a ⊢ ∀x. P x ⟶ Q a&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_11: &lt;br /&gt;
  assumes &amp;quot;(∃x. P x) ⟶ Q a&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀x. P x ⟶ Q a&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 12. Demostrar&lt;br /&gt;
       ∀x. P x ⟶ Q a ⊢ ∃ x. P x ⟶ Q a&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_12: &lt;br /&gt;
  assumes &amp;quot;∀x. P x ⟶ Q a&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃x. P x ⟶ Q a&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 13. Demostrar&lt;br /&gt;
       (∀x. P x) ∨ (∀x. Q x) ⊢ ∀x. P x ∨ Q x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_13: &lt;br /&gt;
  assumes &amp;quot;(∀x. P x) ∨ (∀x. Q x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀x. P x ∨ Q x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 14. Demostrar&lt;br /&gt;
       ∃x. P x ∧ Q x ⊢ (∃x. P x) ∧ (∃x. Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_14: &lt;br /&gt;
  assumes &amp;quot;∃x. P x ∧ Q x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;(∃x. P x) ∧ (∃x. Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 15. Demostrar&lt;br /&gt;
       ∀x y. P y ⟶ Q x ⊢ (∃y. P y) ⟶ (∀x. Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_15: &lt;br /&gt;
  assumes &amp;quot;∀x y. P y ⟶ Q x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;(∃y. P y) ⟶ (∀x. Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 16. Demostrar&lt;br /&gt;
       ¬(∀x. ¬(P x)) ⊢ ∃x. P x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_16: &lt;br /&gt;
  assumes &amp;quot;¬(∀x. ¬(P x))&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃x. P x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 17. Demostrar&lt;br /&gt;
       ∀x. ¬(P x) ⊢ ¬(∃x. P x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_17: &lt;br /&gt;
  assumes &amp;quot;∀x. ¬(P x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;¬(∃x. P x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 18. Demostrar&lt;br /&gt;
       ∃x. P x ⊢ ¬(∀x. ¬(P x))&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_18: &lt;br /&gt;
  assumes &amp;quot;∃x. P x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;¬(∀x. ¬(P x))&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 19. Demostrar&lt;br /&gt;
       P a ⟶ (∀x. Q x) ⊢ ∀x. P a ⟶ Q x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_19: &lt;br /&gt;
  assumes &amp;quot;P a ⟶ (∀x. Q x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀x. P a ⟶ Q x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 20. Demostrar&lt;br /&gt;
       {∀x y z. R x y ∧ R y z ⟶ R x z, &lt;br /&gt;
        ∀x. ¬(R x x)}&lt;br /&gt;
       ⊢ ∀x y. R x y ⟶ ¬(R y x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_20: &lt;br /&gt;
  assumes &amp;quot;∀x y z. R x y ∧ R y z ⟶ R x z&amp;quot;&lt;br /&gt;
          &amp;quot;∀x. ¬(R x x)&amp;quot; &lt;br /&gt;
  shows   &amp;quot;∀x y. R x y ⟶ ¬(R y x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 21. Demostrar&lt;br /&gt;
     {∀x. P x ∨ Q x, ∃x. ¬(Q x), ∀x. R x ⟶ ¬(P x)} ⊢ ∃x. ¬(R x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_21:&lt;br /&gt;
  assumes &amp;quot;∀x. P x ∨ Q x&amp;quot; &lt;br /&gt;
          &amp;quot;∃x. ¬(Q x)&amp;quot; &lt;br /&gt;
          &amp;quot;∀x. R x ⟶ ¬(P x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃x. ¬(R x)&amp;quot; &lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 22. Demostrar&lt;br /&gt;
     {∀x. P x ⟶ Q x ∨ R x, ¬(∃x. P x ∧ R x)} ⊢ ∀x. P x ⟶ Q x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_22:&lt;br /&gt;
  assumes &amp;quot;∀x. P x ⟶ Q x ∨ R x&amp;quot; &lt;br /&gt;
          &amp;quot;¬(∃x. P x ∧ R x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀x. P x ⟶ Q x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 23. Demostrar&lt;br /&gt;
     ∃x y. R x y ∨ R y x ⊢ ∃x y. R x y&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_23:&lt;br /&gt;
  assumes &amp;quot;∃x y. R x y ∨ R y x&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃x y. R x y&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 24. Demostrar&lt;br /&gt;
       (∃x. ∀y. P x y) ⟶ (∀y. ∃x. P x y)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_24: &lt;br /&gt;
  &amp;quot;(∃x. ∀y. P x y) ⟶ (∀y. ∃x. P x y)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 25. Demostrar&lt;br /&gt;
       (∀x. P x ⟶ Q) ⟷ ((∃x. P x) ⟶ Q)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_25: &lt;br /&gt;
  &amp;quot;(∀x. P x ⟶ Q) ⟷ ((∃x. P x) ⟶ Q)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 26. Demostrar&lt;br /&gt;
       ((∀x. P x) ∧ (∀x. Q x)) ⟷ (∀x. P x ∧ Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_26: &lt;br /&gt;
  &amp;quot;((∀x. P x) ∧ (∀x. Q x)) ⟷ (∀x. P x ∧ Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 27. Demostrar o refutar&lt;br /&gt;
       ((∀x. P x) ∨ (∀x. Q x)) ⟷ (∀x. P x ∨ Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_27: &lt;br /&gt;
  &amp;quot;((∀x. P x) ∨ (∀x. Q x)) ⟷ (∀x. P x ∨ Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 28. Demostrar o refutar&lt;br /&gt;
       ((∃x. P x) ∨ (∃x. Q x)) ⟷ (∃x. P x ∨ Q x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_28: &lt;br /&gt;
  &amp;quot;((∃x. P x) ∨ (∃x. Q x)) ⟷ (∃x. P x ∨ Q x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 29. Demostrar o refutar&lt;br /&gt;
       (∀x. ∃y. P x y) ⟶ (∃y. ∀x. P x y)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_29: &lt;br /&gt;
  &amp;quot;(∀x. ∃y. P x y) ⟶ (∃y. ∀x. P x y)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 30. Demostrar o refutar&lt;br /&gt;
       (¬(∀x. P x)) ⟷ (∃x. ¬P x)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_30: &lt;br /&gt;
  &amp;quot;(¬(∀x. P x)) ⟷ (∃x. ¬P x)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
section {* Ejercicios sobre igualdad *}&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 31. Demostrar o refutar&lt;br /&gt;
       P a ⟹ ∀x. x = a ⟶ P x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_31b:&lt;br /&gt;
  assumes &amp;quot;P a&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∀x. x = a ⟶ P x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 32. Demostrar o refutar&lt;br /&gt;
       ∃x y. R x y ∨ R y x; ¬(∃x. R x x)⟧ ⟹ ∃x y. x ≠ y&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_32:&lt;br /&gt;
  fixes R :: &amp;quot;&amp;#039;c ⇒ &amp;#039;c ⇒ bool&amp;quot;&lt;br /&gt;
  assumes &amp;quot;∃x y. R x y ∨ R y x&amp;quot;&lt;br /&gt;
          &amp;quot;¬(∃x. R x x)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃(x::&amp;#039;c) y. x ≠ y&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 33. Demostrar o refutar&lt;br /&gt;
     {∀x. P a x x, &lt;br /&gt;
      ∀x y z. P x y z ⟶ P (f x) y (f z)} &lt;br /&gt;
     ⊢ P (f a) a (f a)&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_33:&lt;br /&gt;
  assumes &amp;quot;∀x. P a x x&amp;quot;&lt;br /&gt;
          &amp;quot;∀x y z. P x y z ⟶ P (f x) y (f z)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;P (f a) a (f a)&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 34. Demostrar o refutar&lt;br /&gt;
     {∀x. P a x x, &lt;br /&gt;
      ∀x y z. P x y z ⟶ P (f x) y (f z)⟧&lt;br /&gt;
     ⊢ ∃z. P (f a) z (f (f a))&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_34b:&lt;br /&gt;
  assumes &amp;quot;∀x. P a x x&amp;quot; &lt;br /&gt;
          &amp;quot;∀x y z. P x y z ⟶ P (f x) y (f z)&amp;quot;&lt;br /&gt;
  shows   &amp;quot;∃z. P (f a) z (f (f a))&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 35. Demostrar o refutar&lt;br /&gt;
     {∀y. Q a y, &lt;br /&gt;
      ∀x y. Q x y ⟶ Q (s x) (s y)} &lt;br /&gt;
     ⊢ ∃z. Qa z ∧ Q z (s (s a))&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_35:&lt;br /&gt;
  assumes &amp;quot;∀y. Q a y&amp;quot; &lt;br /&gt;
          &amp;quot;∀x y. Q x y ⟶ Q (s x) (s y)&amp;quot; &lt;br /&gt;
  shows   &amp;quot;∃z. Q a z ∧ Q z (s (s a))&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 36. Demostrar o refutar&lt;br /&gt;
     {x = f x, odd (f x)} ⊢ odd x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_36b:&lt;br /&gt;
  &amp;quot;⟦x = f x; odd (f x)⟧ ⟹ odd x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
text {* --------------------------------------------------------------- &lt;br /&gt;
  Ejercicio 37. Demostrar o refutar&lt;br /&gt;
     {x = f x, triple (f x) (f x) x} ⊢ triple x x x&lt;br /&gt;
  ------------------------------------------------------------------ *}&lt;br /&gt;
&lt;br /&gt;
lemma ejercicio_37b:&lt;br /&gt;
  &amp;quot;⟦x = f x; triple (f x) (f x) x⟧ ⟹ triple x x x&amp;quot;&lt;br /&gt;
oops&lt;br /&gt;
&lt;br /&gt;
end&lt;br /&gt;
&amp;lt;/source&amp;gt;&lt;/div&gt;</summary>
		<author><name>Jalonso</name></author>
		
	</entry>
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