===== Indexed union =====
==== Set ====
| @#55CCEE: context     | @#55CCEE: $f:I\to X$ |
| @#FFBB00: definiendum | @#FFBB00: $\bigcup_{i\in I,\ f} X_i \equiv \bigcup \mathrm{im}(f)$ |

==== Discussion ====
For $f=\mathrm{id}$, the set is indexing itself and the indexed union is just the arbitrary union $\bigcup_{i\in I} X_i = \bigcup X$.
==== Parents ====
=== Refinement of ===
[[Arbitrary union]]
=== Context ===
[[Image]]