Equals pointer in ternary search tree and limitations

Question

HERE it is said that each node in a ternary search tree has three pointers. Left, right and equals. But in the example tree for {CAT, BUGS, CATS, UP}, How is that equals pointer of 'C' points to 'A' ? 'C' and 'A' are not equal right ?

And if a node can have only three pointers, how will a ternary tree represent a set of keys like {CAB,CBA,CDA,CEA,CFA} ?

Answer 1

A1: The equals pointer marks the continuation of the current prefix. Thus C -> CA -> CAT -> CATS but not C -> CB[UGS].

A2: This would be a ternary search tree for the given set of expressions ( termination flags and leaf node expansion omitted):

                                           C
                                           |
                      +--------------------+---------------------+
                      |                    |                     | 
                     /l/                  /e/                   /r/
                      |                    |                     | 
                      C                    D                     C     
                      |                    |                     |     
          +-----------+----+           +---+---+             +---+-----------+  
          |           |    |           |   |   |             |   |           |     
         /l/         /e/  /r/         /l/ /e/ /r/           /l/ /e/         /r/    
          |           |    |           |   |   |             |   |           |     
          C           B    x           x   A   x             x   E           C     
          |           |                                          |           |     
          |           |                                          |           |     
      +---+---+   +---+---+                                  +---+---+   +---+---+ 
      |   |   |   |   |   |                                  |   |   |   |   |   | 
     /l/ /e/ /r/ /l/ /e/ /r/                                /l/ /e/ /r/ /l/ /e/ /r/
      |   |   |   |   |   |                                  |   |   |   |   |   | 
      x   A   x   x   A   x                                  x   A   x   x   F   x 
          |                                                                  |     
          |                                                                  |     
      +---+---+                                                          +---+---+ 
      |   |   |                                                          |   |   | 
     /l/ /e/ /r/                                                        /l/ /e/ /r/
      |   |   |                                                          |   |   | 
      x   B   x                                                          x   A   x