<?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 Funciones)</title><link>https://jaalonso.github.io/calculemus/</link><description></description><atom:link href="https://jaalonso.github.io/calculemus/es/categories/cat_funciones.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;
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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>Wed, 14 Oct 2026 18:49:41 GMT</lastBuildDate><generator>Nikola (getnikola.com)</generator><docs>http://blogs.law.harvard.edu/tech/rss</docs><item><title>Demostraciones de "s ∪ f⁻¹[v] ⊆ f⁻¹[f[s] ∪ v]"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/25-union_con_la_imagen_inversaes/</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
\[ s ∪ f⁻¹[v] ⊆ f⁻¹[f[s] ∪ v] \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="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;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;v&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;β&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="n"&gt;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;v&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;f&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;v&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;Union_con_la_imagen_inversa&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 ∪ f -` v ⊆ f -` (f ` s ∪ v)"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/25-union_con_la_imagen_inversaes/"&gt;Leer más…&lt;/a&gt; (quedan 6 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/25-union_con_la_imagen_inversaes/</guid><pubDate>Fri, 25 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f[s] ∩ v = f[s ∩ f⁻¹[v]​]​"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/24-interseccion_con_la_imagen_inversaes/</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
\[ f[s] ∩ v = f[s ∩ f⁻¹[v]] \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="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;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;v&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;β&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;f&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="n"&gt;v&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;f&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;v&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;Interseccion_con_la_imagen_inversa&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;"(f ` s) ∩ v = f ` (s ∩ f -` v)"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/24-interseccion_con_la_imagen_inversaes/"&gt;Leer más…&lt;/a&gt; (quedan 11 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/24-interseccion_con_la_imagen_inversaes/</guid><pubDate>Thu, 24 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f[s ∪ f⁻¹[v]] ⊆ f[s] ∪ v"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/23-union_con_la_imagenes/</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
\[ f[s ∪ f⁻¹[v]] ⊆ f[s] ∪ v \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="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;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;v&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;β&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;f&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;v&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;f&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;v&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_la_imagen&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;"f ` (s ∪ f -` v) ⊆ f ` s ∪ v"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/23-union_con_la_imagenes/"&gt;Leer más…&lt;/a&gt; (quedan 5 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/23-union_con_la_imagenes/</guid><pubDate>Wed, 23 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f[s] ∩ t = f[s ∩ f⁻¹[t]]"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/22-interseccion_con_la_imagenes/</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
\[ f[s] ∩ t = f[s ∩ f⁻¹[t]] \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="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;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;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;β&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;f&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="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;f&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&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;Interseccion_con_la_imagen&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;"(f ` s) ∩ v = f ` (s ∩ f -` v)"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/22-interseccion_con_la_imagenes/"&gt;Leer más…&lt;/a&gt; (quedan 11 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/22-interseccion_con_la_imagenes/</guid><pubDate>Tue, 22 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f[s] \ f[t] ⊆ f[s \ t]"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/21-imagen_de_la_diferencia_de_conjuntoses/</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
\[f[s] \setminus f[t] ⊆ f[s \setminus t] \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="n"&gt;f&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;f&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;f&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;Imagen_de_la_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;"f ` s - f ` t ⊆ f ` (s - t)"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/21-imagen_de_la_diferencia_de_conjuntoses/"&gt;Leer más…&lt;/a&gt; (quedan 5 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/21-imagen_de_la_diferencia_de_conjuntoses/</guid><pubDate>Mon, 21 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Si f es inyectiva, entonces f[s] ∩ f[t] ⊆ f[s ∩ t]</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/20-imagen_de_la_interseccion_de_aplicaciones_inyectivases/</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 si \(f\) es inyectiva, entonces
\[ f[s] ∩ f[t] ⊆ f[s ∩ t] \]&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.Function&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="n"&gt;h&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;Injective&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;f&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;f&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;f&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;f&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;Imagen_de_la_interseccion_de_aplicaciones_inyectivas&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="kp"&gt;assumes&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"inj f"&lt;/span&gt;
&lt;span class="w"&gt;  &lt;/span&gt;&lt;span class="kp"&gt;shows&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"f ` s ∩ f ` t ⊆ f ` (s ∩ t)"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/20-imagen_de_la_interseccion_de_aplicaciones_inyectivases/"&gt;Leer más…&lt;/a&gt; (quedan 5 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/20-imagen_de_la_interseccion_de_aplicaciones_inyectivases/</guid><pubDate>Sun, 20 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f[s ∩ t] ⊆ f[s] ∩ f[t]​"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/19-imagen_de_la_intersecciones/</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
\[ f[s ∩ t] ⊆ f[s] ∩ f[t]​ \]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="n"&gt;f&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;f&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;f&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;Imagen_de_la_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;"f ` (s ∩ t) ⊆ f ` s ∩ f ` t"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/19-imagen_de_la_intersecciones/"&gt;Leer más…&lt;/a&gt; (quedan 4 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/19-imagen_de_la_intersecciones/</guid><pubDate>Sat, 19 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Demostraciones de "f⁻¹[A ∪ B] = f⁻¹[A] ∪ f⁻¹[B]​"</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/18-imagen_inversa_de_la_uniones/</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
\[f⁻¹[A ∪ B] = f⁻¹[A] ∪ f⁻¹[B]\]&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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;A&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;B&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;β&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="o"&gt;(&lt;/span&gt;&lt;span class="n"&gt;A&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;B&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;A&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;B&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 IsabelleHOL:&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;Imagen_inversa_de_la_union&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;"f -` (u ∪ v) = f -` u ∪ f -` v"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/18-imagen_inversa_de_la_uniones/"&gt;Leer más…&lt;/a&gt; (quedan 8 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/18-imagen_inversa_de_la_uniones/</guid><pubDate>Fri, 18 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Monotonía de la imagen inversa</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/17-monotonia_de_la_imagen_inversaes/</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 si \(u ⊆ v\), entonces \(f⁻¹[u] ⊆ f⁻¹[v]\).&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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;u&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;v&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;β&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="n"&gt;h&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;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;v&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&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;f&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="bp"&gt;⁻¹'&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;v&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;Monotonia_de_la_imagen_inversa&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="kp"&gt;assumes&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"u ⊆ v"&lt;/span&gt;
&lt;span class="w"&gt;  &lt;/span&gt;&lt;span class="kp"&gt;shows&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"f -` u ⊆ f -` v"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/17-monotonia_de_la_imagen_inversaes/"&gt;Leer más…&lt;/a&gt; (quedan 3 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/17-monotonia_de_la_imagen_inversaes/</guid><pubDate>Thu, 17 Apr 2025 04:00:00 GMT</pubDate></item><item><title>Monotonía de la imagen de conjuntos</title><link>https://jaalonso.github.io/calculemus/es/posts/2025/04/15-monotonia_de_la_imagen_de_conjuntoses/</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 si \(s ⊆ t\), entonces \(f[s] ⊆ f[t]\).&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.Function&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="n"&gt;β&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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;_&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;f&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;α&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;β&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="n"&gt;h&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="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="w"&gt; &lt;/span&gt;&lt;span class="n"&gt;f&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;f&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;Monotonia_de_la_imagen_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="kp"&gt;assumes&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"s ⊆ t"&lt;/span&gt;
&lt;span class="w"&gt;  &lt;/span&gt;&lt;span class="kp"&gt;shows&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s"&gt;"f ` s ⊆ f ` t"&lt;/span&gt;
&lt;span class="gr"&gt;sorry&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/es/posts/2025/04/15-monotonia_de_la_imagen_de_conjuntoses/"&gt;Leer más…&lt;/a&gt; (quedan 3 minutos de lectura)&lt;/p&gt;&lt;/div&gt;</description><guid>https://jaalonso.github.io/calculemus/es/posts/2025/04/15-monotonia_de_la_imagen_de_conjuntoses/</guid><pubDate>Tue, 15 Apr 2025 04:00:00 GMT</pubDate></item></channel></rss>