Update textbook.es.md

00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.es.md

@@ -4,6 +4,14 @@ published: false
 visible: false
 ---
 
+$`\def\oiint{\displaystyle\mathop{{\iint}\mkern-18mu \scriptsize \bigcirc}}`$
+$`\def\Ltau{\Large{\tau}\normalsize}`$
+$`\def\Sopen{\mathscr{S}_{\smile}}`$
+$`\def\Sclosed{\mathscr{S}_{\displaystyle\tiny\bigcirc}}`$
+$`\def\Ssclosed{\mathscr{S}_{\scriptsize\bigcirc}}`$
+$`\def\PSopen{\mathscr{S}_{\smile}}`$
+$`\def\PSclosed{\mathscr{S}_{\displaystyle\tiny\bigcirc}}`$
+
 ### Elementos del curso : las sistemas de coordenadas / Eléments de cours : les systèmes
 de coordonnées / Course elements : the coordinate systems