******** fig9.66 **********

	/* assign low.  Also check for articulation points */

	void
	assign_low( vertex v )
	{
		vertex w;

/*1*/		low[v] = num[v];		/* Rule 1 */
/*2*/		for each w adjacent to v
		{
/*3*/			if( num[w] > num[v] )	/* forward edge */
			{
/*4*/				assign_low( w );
/*5*/				if( low[w] >= num[v] )
/*6*/					printf("%v is an articulation point\n", v );
/*7*/				low[v] = min( low[v], low[w] );	/* Rule 3 */
			}
			else
/*8*/			if( parent[v] != w )	/* back edge */
/*9*/				low[v] = min( low[v], num[w] );	/* Rule 2 */
		}
	}