\mathop L\limits_{k = 1}^n {g_k}(z) = {g_n} \circ {g_{n - 1}} \circ \cdots \circ {g_1}(z)
{G_n}(z) = \mathop R\limits_{k = 1}^n {g_k}(z)\mathop L\limits_{k = 1}^\infty {g_k}(z) = \mathop {\lim }\limits_{n \to \infty } {G_n}(z)
and
\mathop R\limits_{k = 1}^n {f_k}(z) = {f_1} \circ {f_2} \circ...