if the
input is 
.
Finally, we construct a DPDA 
that emulates . In this emulation,
one step of might be emulated by more than one step of . We
shall use the same state names as much as possible.
A DPDA must pop exactly one symbol, and cannot ``peek'' at the next
input symbol without reading it.
In order to emulate a step of that pops more than one symbol,
intermediate states are introduced, such as 4.1, 4.2, 7.1.
can read a symbol and store it into
a buffer. When the emulated is supposed to read,
examines the buffer. The buffer is implemented by proliferating the states.
For example, state 3.b is identical to state 3, except that b is in
the buffer.
