Update mkdocs.yml

mkdocs.yml

@@ -8,6 +8,9 @@ nav:
   - Intro: 'index.md'
   - Complex Numbers: '1_complex_numbers.md'
   - Coordinates: '2_coordinates.md'
+  - Vector spaces: '3_vector_spaces.md'
+  - Vector spaces in quantum mechanics: '4_vector_spaces_QM.md'
+  - Operators in quantum mechanics: '5_operators_QM.md'
 theme:
   name: material
   custom_dir: theme