Definition 17.3.3 (Generated $\lambda$-System).label Let $X$ be a set and $\ce \subset 2^{X}$, then the smallest $\lambda$-system $\lambda(\ce)$ over $X$ containing $\ce$ is the $\lambda$-system generated by $\ce$.
Definition 17.3.3 (Generated $\lambda$-System).label Let $X$ be a set and $\ce \subset 2^{X}$, then the smallest $\lambda$-system $\lambda(\ce)$ over $X$ containing $\ce$ is the $\lambda$-system generated by $\ce$.