1 Answers
In category theory, a branch of abstract mathematics, a tower is defined as follows. Let I {\displaystyle {\mathcal {I}}} be the poset
of whole numbers in reverse order, regarded as a category. A tower of objects in a category A {\displaystyle {\mathcal {A}}} is a functor from I {\displaystyle {\mathcal {I}}} to A {\displaystyle {\mathcal {A}}}.
In other words, a tower is a family of objects { A i } i ≥ 0 {\displaystyle \{A_{i}\}_{i\geq 0}} in A {\displaystyle {\mathcal {A}}} where there exists a map
and the composition