L19_A
        8.3 Lebesque's Theorem
             (1)Theorem 2
             (2)Note

L19_B
        8.3 Lebesque's Theorem
              (1)Note(cont.):prove or disprovef is integrable
              (2)Prop: If A and B have volume, then A∪B,
                            A∩B and A\\\\B have volume.
        8.4 Properties of the integral
             (3)Theorem

L19_C
        8.4 Properties of the integral
            (1)Theorem(cont.)

L19_D
        8.4 Properties of the integral
             (1)Theorem(cont.)
             (2)Prop:If A and B have volume, then A∪B,
                          A∩B and A\\\\B have volume.