Update src/4_vector_spaces_QM.md, mkdocs.yml

mkdocs.yml

@@ -6,14 +6,14 @@ site_description: |
   Lecture notes for the TU Delft course TN3105 - Mathematics for Quantum Physics
 nav:
   - Introduction: 'index.md'
-  - Complex numbers: '1_complex_numbers.md'
-  - Coordinate systems: '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'
-  - Eigenvectors and eigenvalues: '6_eigenvectors_QM.md'
-  - Differential equations 1: '7_differential_equations_1.md'
-  - Differential equations 2: '8_differential_equations_2.md'
+  - 1. Complex numbers: '1_complex_numbers.md'
+  - 2. Coordinate systems: '2_coordinates.md'
+  - 3. Vector spaces: '3_vector_spaces.md'
+  - 4. Vector spaces in quantum mechanics: '4_vector_spaces_QM.md'
+  - 5. Operators in quantum mechanics: '5_operators_QM.md'
+  - 6. Eigenvectors and eigenvalues: '6_eigenvectors_QM.md'
+  - 7. Differential equations 1: '7_differential_equations_1.md'
+  - 8. Differential equations 2: '8_differential_equations_2.md'
 
 theme:
   name: material

src/4_vector_spaces_QM.md

@@ -244,7 +244,7 @@ cannot represent physical states. We show below an explicit example of a normali
      $$
      as required to ensure the probabilistic description of the state vector.
 
-## Problems
+## 4.5. Problems
 
 **1)** [:grinning:] *The inner product*