  Let $\scr A^*=\{l_1,l_2,\cdots,l_n\}$ be a line arrangement in $\Bbb{CP}^2$,
i.e., a collection of distinct lines in $\Bbb{CP}^2$. Let $L(\scr A^*)$ be the
set of all intersections of elements of $A^*$ partially ordered by $X\leq
Y\Leftrightarrow Y\subseteq X$. Let $M(\scr A^*)$ be $\Bbb{CP}^2-\bigcup\scr
A^*$ where $\bigcup\scr A^*= \bigcup\{l_i\colon\ 1\leq i\leq n\}$. The central
problem of the theory of arrangement of lines in $\Bbb{CP}^2$ is the
relationship between $M(\scr A^*)$ and $L(\scr A^*)$.
