Remark 220.127.116.11. The preceding discussion has centered around the theory of limits. There is also a dual theory of colimits in the $\infty $-categorical setting, which can be obtained by passing to opposite $\infty $-categories. Every assertion concerning limits has a counterpart for colimits (and vice versa). We will often use this implicitly (for example, by stating a result only for colimits but later using the dual assertion for limits).