diff --git a/grammar.js b/grammar.js
index 3e509f9..35d34bd 100644
--- a/grammar.js
+++ b/grammar.js
@@ -175,7 +175,7 @@ module.exports = grammar({
     command : $ => '@include',
 
     identifier : $ => /[a-zA-Z_]\w*/,
-    symbol     : $ => /[!@#$%^&*-+=<>,./?{}\\|`~'\"∧∨⊙×≅]+/,
+    symbol     : $ => /[!@#$%^&*-+=<>,./?{}\\|`~'\"∧∨⊙×≅]+∈⊆⊂⊃⊇/,
 
   }
 });