******** fig6.54 **********

	/* Merge two equal-sized binomial trees */

	tree_ptr
	merge_tree( tree_ptr T1, tree_ptr T2 )
	{
		if( T1->element > T2->element )
			return merge_tree( T2, T1 );
		if( T1->rank++ == 0 )
			T1->f_child = T2;
		else
		{
			T2->l_sib = T1->f_child->l_sib;
			T2->l_sib->r_sib = T2;
			T1->f_child->l_sib = T2;
		}
		return T1;
	}