{cases}
    &amp;
    \begin{array}{l}
    \text{if \(s_{k+2} \lt 0\)} \\
    \text{if \(s_{k+2} \ge 0\) and \(t \gt 1 - s_{k+2}\)} \\
    \text{otherwise}
    \end{array}

    \end{array}$$

    and the blending functions \(f\), \(g\), and \(h\) are defined as follows:

    $$\begin{array}{l}

    F(u, p) = u^3(10 - p + (2p - 15)u + (6 - p)u^2) \\

    f(n, d) = F(n/d, 2d^2) \\

    g(u, q) = u(q + u(2q + u(8 - 12q + u(14q - 11 + u(4 - 5q))))) \\

    h(u, q) = u(q + u(2q + u^2(-2q - uq))) \\

    \end{arr