Symbol Invariant of Partition and the Construction
  The symbol is used to describe the Springer correspondence for the classical
groups. We propose equivalent definitions of symbols for rigid partitions in
the $B_n$, $C_n$, and $D_n$ theories uniformly. Analysing the new definition of
symbol in detail, we give rules to construct symbol of a partition, which are
easy to remember and to operate on. We introduce formal operations of a
partition, which reduce the difficulties in the proof of the construction
rules. According these rules, we give a closed formula of symbols for different
theories uniformly. As applications, previous results can be illustrated more
clearly by the construction rules of symbol.
