L2_B
      6.4 Conditions for differentiability (cont.)
            (1)Question

    
L2_C
      6.3 Continuity of  Differentiable mappings
            (1)Question
            (2)Lemma

L2_D
      6.3 Continuity of  Differentiable mappings(cont.)
            (1)Lemma(cont.)
            (2)Property (local Lipschitz property)
            (3)Definition: (vertor-value) function