Mencken 
                                                  |
                                             Wichmannshausen
                                                  |
                                               Hausen
                                                  |
                                               Kaestner
                                              /    \   \
                                         Pfaff      \   \
                                         |           \   Lichtenberg
               Littrov                 Gauss          \    |
                   |                     |   \         \   |
                Brashman                 |    Bessel   Brandes
                   |                     |        |   /
               Chebyshev             Guderman    Scherk
            /      |      \              |         |
           /       |       Lyapunov  Weierstrass  Kummer
          /        |         |             \     /
       Korkin   Markov    Steklov          Bugaev
             \     /         |                |
              Gunter      Smirnov          Egorov
                    \       /                 |  
                     Sobolev             Petrovsky
                            \            /
                            Ladyzhenskaya      Fock         
                                       \       /
                  Kato                  Faddeev
                      \                   |
                       Balslev          Venkov
                              \        /
                               Risager