<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="../assets/xml/rss.xsl" media="all"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Calculemus (Publicaciones sobre Diferencia)</title><link>https://jaalonso.github.io/calculemus/</link><description></description><atom:link href="https://jaalonso.github.io/calculemus/tags/diferencia.xml" rel="self" type="application/rss+xml"></atom:link><language>es</language><copyright>Contents © 2026 &lt;a href="mailto:"&gt;José A. Alonso&lt;/a&gt; 
&lt;a rel="license" href="https://creativecommons.org/licenses/by-nc-sa/4.0/"&gt;
&lt;img alt="Creative Commons License BY-NC-SA"
style="border-width:0; margin-bottom:12px;"
src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png"&gt;&lt;/a&gt;</copyright><lastBuildDate>Sun, 18 Oct 2026 17:47:01 GMT</lastBuildDate><generator>Nikola (getnikola.com)</generator><docs>http://blogs.law.harvard.edu/tech/rss</docs><item><title>Demostraciones de "(s \ t) ∪ (t \ s) = (s ∪ t) \ (s ∩ t)"</title><link>https://jaalonso.github.io/calculemus/posts/2021/05/28-diferencia_de_union_e_interseccion/</link><dc:creator>José A. Alonso</dc:creator><description>&lt;div&gt;&lt;hr&gt;
&lt;p&gt;Demostrar con Lean4 y con Isabelle/HOL que
\[ (s \setminus t) ∪ (t \setminus s) = (s ∪ t) \setminus (s ∩ t) \]&lt;/p&gt;
&lt;p&gt;Para ello, completar la siguiente teoría de Lean4:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Data.Set.Basic&lt;/span&gt;
&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Tactic&lt;/span&gt;

&lt;span class="kn"&gt;open&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;

&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;{&lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="kt"&gt;Type&lt;/span&gt;&lt;span class="o"&gt;}&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;

&lt;span class="kd"&gt;example&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;=&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∩&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:=&lt;/span&gt;
&lt;span class="kd"&gt;by&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="gr"&gt;sorry&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;p&gt;y la siguiente teoría de Isabelle/HOL:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="k"&gt;theory&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Diferencia_de_union_e_interseccion&lt;/span&gt;
&lt;span class="kp"&gt;imports&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Main&lt;/span&gt;
&lt;span class="k"&gt;begin&lt;/span&gt;

&lt;span class="kn"&gt;lemma&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"(s - t) ∪ (t - s) = (s ∪ t) - (s ∩ t)"&lt;/span&gt;
&lt;span class="gr"&gt;oops&lt;/span&gt;

&lt;span class="k"&gt;end&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;hr&gt;
&lt;p&gt;&lt;a href="https://jaalonso.github.io/calculemus/posts/2021/05/28-diferencia_de_union_e_interseccion/"&gt;Leer más…&lt;/a&gt; (quedan 14 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><category>Conjuntos</category><category>Diferencia</category><category>Intersección</category><category>Isabelle</category><category>Lean4</category><category>Unión</category><guid>https://jaalonso.github.io/calculemus/posts/2021/05/28-diferencia_de_union_e_interseccion/</guid><pubDate>Fri, 28 May 2021 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "(s \ t) ∪ t = s ∪ t"</title><link>https://jaalonso.github.io/calculemus/posts/2021/05/27-union_con_su_diferencia/</link><dc:creator>José A. Alonso</dc:creator><description>&lt;div&gt;&lt;hr&gt;
&lt;p&gt;Demostrar con Lean4 y con Isabelle/HOL que
\[ (s \setminus t) ∪ t = s ∪ t \]&lt;/p&gt;
&lt;p&gt;Para ello, completar la siguiente teoría de Lean4:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Data.Set.Basic&lt;/span&gt;
&lt;span class="kn"&gt;open&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;

&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;{&lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="kt"&gt;Type&lt;/span&gt;&lt;span class="o"&gt;}&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;

&lt;span class="kd"&gt;example&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\\&lt;/span&gt;&lt;span class="n"&gt;setminus&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;=&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:=&lt;/span&gt;
&lt;span class="kd"&gt;by&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="gr"&gt;sorry&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;p&gt;y la siguiente teoría de Isabelle/HOL:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="k"&gt;theory&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Union_con_su_diferencia&lt;/span&gt;
&lt;span class="kp"&gt;imports&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Main&lt;/span&gt;
&lt;span class="k"&gt;begin&lt;/span&gt;

&lt;span class="kn"&gt;lemma&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"(s - t) ∪ t = s ∪ t"&lt;/span&gt;
&lt;span class="gr"&gt;oops&lt;/span&gt;

&lt;span class="k"&gt;end&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;hr&gt;
&lt;p&gt;&lt;a href="https://jaalonso.github.io/calculemus/posts/2021/05/27-union_con_su_diferencia/"&gt;Leer más…&lt;/a&gt; (quedan 6 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><category>Conjuntos</category><category>Diferencia</category><category>Isabelle</category><category>Lean4</category><category>Unión</category><guid>https://jaalonso.github.io/calculemus/posts/2021/05/27-union_con_su_diferencia/</guid><pubDate>Thu, 27 May 2021 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "s \ (t ∪ u) ⊆ (s \ t) \ u"</title><link>https://jaalonso.github.io/calculemus/posts/2021/05/21-diferencia_de_diferencia_de_conjuntos_2/</link><dc:creator>José A. Alonso</dc:creator><description>&lt;div&gt;&lt;hr&gt;
&lt;p&gt;Demostrar con Lean4 y con Isabelle/HOL que
\[ s \setminus (t ∪ u) ⊆ (s \setminus t) \setminus u \]&lt;/p&gt;
&lt;p&gt;Para ello, completar la siguiente teoría de Lean4:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Data.Set.Basic&lt;/span&gt;
&lt;span class="kn"&gt;open&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;{&lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="kt"&gt;Type&lt;/span&gt;&lt;span class="o"&gt;}&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;

&lt;span class="kd"&gt;example&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⊆&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:=&lt;/span&gt;
&lt;span class="kd"&gt;by&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="gr"&gt;sorry&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;p&gt;y la siguiente teoría de Isabelle/HOL:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="k"&gt;theory&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Diferencia_de_diferencia_de_conjuntos_2&lt;/span&gt;
&lt;span class="kp"&gt;imports&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Main&lt;/span&gt;
&lt;span class="k"&gt;begin&lt;/span&gt;

&lt;span class="kn"&gt;lemma&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"(s - t) - u ⊆ s - (t ∪ u)"&lt;/span&gt;
&lt;span class="gr"&gt;oops&lt;/span&gt;

&lt;span class="k"&gt;end&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;hr&gt;
&lt;p&gt;&lt;a href="https://jaalonso.github.io/calculemus/posts/2021/05/21-diferencia_de_diferencia_de_conjuntos_2/"&gt;Leer más…&lt;/a&gt; (quedan 4 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><category>Conjuntos</category><category>Diferencia</category><category>Inclusióm</category><category>Isabelle</category><category>Lean4</category><category>Unión</category><guid>https://jaalonso.github.io/calculemus/posts/2021/05/21-diferencia_de_diferencia_de_conjuntos_2/</guid><pubDate>Fri, 21 May 2021 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "(s - t) - u ⊆ s - (t ∪ u)"</title><link>https://jaalonso.github.io/calculemus/posts/2021/05/19-diferencia_de_diferencia_de_conjuntos/</link><dc:creator>José A. Alonso</dc:creator><description>&lt;div&gt;&lt;hr&gt;
&lt;p&gt;Demostrar con Lean4 y con Isabelle/HOL que
\[ (s \setminus t) \setminus u ⊆ s \setminus (t ∪ u) \]&lt;/p&gt;
&lt;p&gt;Para ello, completar la siguiente teoría de Lean4:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Data.Set.Basic&lt;/span&gt;
&lt;span class="kn"&gt;import&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Mathlib.Tactic&lt;/span&gt;

&lt;span class="kn"&gt;open&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;{&lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="kt"&gt;Type&lt;/span&gt;&lt;span class="o"&gt;}&lt;/span&gt;
&lt;span class="kd"&gt;variable&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Set&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;α&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;

&lt;span class="kd"&gt;example&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⊆&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;s&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;\&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;t&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;∪&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;u&lt;/span&gt;&lt;span class="o"&gt;)&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;:=&lt;/span&gt;
&lt;span class="kd"&gt;by&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="gr"&gt;sorry&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;p&gt;y la la siguiente teoría de Isabelle/HOL:&lt;/p&gt;
&lt;div class="code"&gt;&lt;pre class="code literal-block"&gt;&lt;span class="k"&gt;theory&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Diferencia_de_diferencia_de_conjuntos&lt;/span&gt;
&lt;span class="kp"&gt;imports&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Main&lt;/span&gt;
&lt;span class="k"&gt;begin&lt;/span&gt;

&lt;span class="kn"&gt;lemma&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"(s - t) - u ⊆ s - (t ∪ u)"&lt;/span&gt;
&lt;span class="gr"&gt;oops&lt;/span&gt;
&lt;/pre&gt;&lt;/div&gt;

&lt;hr&gt;
&lt;p&gt;&lt;a href="https://jaalonso.github.io/calculemus/posts/2021/05/19-diferencia_de_diferencia_de_conjuntos/"&gt;Leer más…&lt;/a&gt; (quedan 4 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><category>Conjuntos</category><category>Diferencia</category><category>Inclusióm</category><category>Isabelle</category><category>Lean4</category><category>Unión</category><guid>https://jaalonso.github.io/calculemus/posts/2021/05/19-diferencia_de_diferencia_de_conjuntos/</guid><pubDate>Wed, 19 May 2021 04:00:00 GMT</pubDate></item></channel></rss>