.  A 0-tuple $$b = (b(0), b(0), b(0), b(0), b(0), b(0))$$ of integers $b(0), b(0), b(0), b(0), b(0), b(0)$ is called a [*bracket* ]{} for the pair $(W, {\Delta})$ if $b(0), b(0)$ satisfy the inequalities $0 \le b(0) \le b(0) \le |W|$ and